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This activity contains 61 questions.

Question 1
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Previously, it was thought that the blending hypothesis explained inheritance. The blending hypothesis maintained that _____.
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Question 2
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The cross-fertilization of two different, but true-breeding, varieties of pea plants will _____.
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Question 3
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When applied to Mendel's experiments, the term true-breeding means a self-fertilization of two plants that produces _____.
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Question 4
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In a certain plant, the alleles A, B, and C are dominant to the alleles a, b, and C. A plant with the genotype AABbcc will have the same phenotype as the plant with the genotype _____.
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Question 5
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A child with cystic fibrosis can be born to two parents who do not have the disease. This is because the disease _____.
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Question 6
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Assume tall (T) is dominant to dwarf (t). If a homozygous dominant true-breeding individual is crossed with a homozygous true-breeding dwarf, the offspring will _____.
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Question 7
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Phenylketonuria (PKU) is an autosomal recessive disorder that can lead to mental retardation and seizures. Using P and p to represent the alleles, what is the genotype of a phenylketonuric person?
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Question 8
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If a homozygous dominant (AA) is crossed with a homozygous recessive (aa) for a given character, the offspring will be _____.
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Question 9
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When you cross two heterozygotes (Aa), the F1 generation will be _____.
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Question 10
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In Mendel's monohybrid cross of true-breeding purple-flowered and white-flowered peas, all members of the F1 generation were of the _____ phenotype because their genotype was _____ for the flower-color gene.
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Question 11
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Huntington's disease is caused by an autosomal dominant allele. If a heterozygous male were to marry a female not carrying the disease, what percentage of the offspring will have Huntington's?
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Question 12
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What is an allele?
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Question 13
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Achondroplasia is a common cause of dwarfism and is an autosomal dominant condition. If a male individual has achondroplasia, which statement below must be true?
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Question 14
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Homologous pairs of chromosomes frequently _____.
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Question 15
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How many loci are shown on the homologous chromosomes in the figure below?

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Question 16
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An AABb individual is mated with another AABb individual. The possible number of genetically different kinds of offspring is _____.
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Question 17
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Pea flowers may be purple (P) or white (p). Pea seeds may be round (R) or wrinkled (r). What proportion of the offspring from the cross PpRr x PpRr will have white flowers and wrinkled seeds?
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Question 18
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You have one tree that produces big yellow apples and another tree that produces small red apples. When the two are crossed, you find that half the offspring trees produce big red apples and half produce big yellow apples. What are the genotypes of the parents? A = big apples; a = small apples; R = red apples; r = yellow apples.
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Question 19
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A couple who both have the ability to roll their tongues have a son who is also a tongue-roller. Tongue-rolling is a dominant characteristic. The son is curious about whether he is homozygous or heterozygous for tongue-rolling. How could he find out?
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Question 20
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Pea plants are tall if they have the genotype TT or Tt, and they are short if they have the genotype tt. A tall plant is crossed with a short plant. Half the offspring are tall, and half are short. This allows us to conclude that the tall plant _____.
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Question 21
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The results of a testcross (that is, the offspring of this cross) were 50% phenotypically dominant and 50% phenotypically recessive. The genotype of the phenotypically dominant parent in this cross was _____.
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Question 22
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What is indicated when a single-character testcross yields offspring in a 1:1 phenotypic ratio?
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Question 23
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Suppose we have a pea plant with purple flowers, determined by the dominant allele P. How might you determine whether the plant is homozygous (PP) or heterozygous (Pp)?
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Question 24
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If each parent can produce 100 genetically distinct gametes, how many genetically distinct offspring can two parents produce?
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Question 25
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A cross is made between two heterozygous pea plants, and observations are made about three characteristics: flower color, seed color, and seed shape. What is the probability that the offspring will be heterozygous for all three characteristics?
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Question 26
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Tay-Sachs disease runs in Rebecca's family. On a family pedigree, she saw a shaded circle. This represented _____.
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Question 27
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Shown in the figure below are a number of traits that are found in humans to be either dominant or recessive. A woman with freckles has children with a man who has no freckles. Their first child has no freckles. What is the probability of her having a child with freckles with the same man?

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Question 28
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John and Jane are planning a family, but since each has a brother who has sickle-cell disease, they are concerned that their children may develop sickle-cell disease. Neither John, Jane, nor their respective parents have the disease. They consult a genetic counselor who tells them that _____.
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Question 29
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When two average-height parents give birth to a child exhibiting achondroplastic dwarfism, it is most likely due to a new mutation. This is because _____.
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Question 30
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Cystic fibrosis, which is usually lethal before the age of reproduction, is a homozygous recessive trait. Even though people with the disease rarely reproduce, cases continue to arise because _____.
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Question 31
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It is far more common to find human genetic disease caused by _____ alleles than by _____ alleles because _____.
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Question 32
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Michelle and Keith are apparently normal, but their daughter was born with alkaptonuria, an inherited metabolic disorder that causes urine to turn black when exposed to air. If alkaptonuria is like most other human hereditary disorders, the probability of their next child being born with alkaptonuria is _____.
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Question 33
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Huntington's disease is an example of a genetic disorder caused by _____.
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Question 34
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Several inherited disorders are much more common in close-knit religious communities, such as the Amish, than in the general population. This is at least partly due to the fact that _____.
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Question 35
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Fetal cells may be removed along with fluid from the womb by a process known as _____.
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Question 36
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The test that is used to determine whether someone possesses a potentially harmful recessive allele is referred to as _____ testing.
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Question 37
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A red bull is crossed with a white cow and all of the offspring are roan, a shade between red and white. This is an example of genes that are _____.
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Question 38
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Flower color in snapdragons is an example of incomplete dominance. If a red-flowered plant is crossed with a white-flowered plant, the F1 generation has pink flowers. If a pink-flowered plant is crossed with a pink-flowered plant, the progeny plants will be _____.
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Question 39
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A male who is homozygous recessive for hypercholesterolemia marries a woman is homozygous dominant. What percentage of their children will have higher than normal blood cholesterol?
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Question 40
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In the figure below, the pink snapdragons are a result of _____ due to incomplete dominance.

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Question 41
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A man who has type B blood and a woman who has type A blood could have children of which of the following phenotypes?
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Question 42
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Two individuals have children with A and B blood types. What are the blood types of the parents?
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Question 43
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If one parent is blood type AB and the other is type O, what fraction of their offspring will be blood type A?
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Question 44
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A woman with type O blood is expecting a child. Her husband is type A. Both the woman's father and her husband's father had type B blood. What is the probability that the child will have type O blood?
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Question 45
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A single allele that controls more than one character is said to be _____.
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Question 46
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In people with sickle-cell disease, the red blood cells break down, clump, and clog the blood vessels. The blood vessels and the broken cells accumulate in the spleen. Among other things, this leads to physical weakness, heart failure, pain, and brain damage. Such a suite of symptoms can be explained by _____.
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Question 47
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The inheritance of height and weight can best be described as _____.
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Question 48
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Two identical twins are raised in different environments. They possess _____ genotypes and _____ phenotypes.
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Question 49
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Seeds from a single sexually reproducing plant are harvested and later planted under identical conditions. What results should be expected?
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Question 50
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As shown in the figure below, at what point in meiosis do the chromosomes segregate from one another?

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Question 51
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If two genes are linked, _____.
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Question 52
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If hair color, eye color, and the presence or absence of freckles were consistently inherited together, the best explanation would be that _____.
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Question 53
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If the two characteristics that Mendel looked at in his dihybrid cross of smooth yellow peas with wrinkled green peas had been controlled by genes that were located close together on the same chromosome, then the F2 generation _____.
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Question 54
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In a particular species of mammal, black hair (B) is dominant to green hair (b), and red eyes (R) are dominant to white eyes (r). When a BbRr individual is mated with a bbrr individual, offspring are produced in a ratio of 5 black hair and red eyes : 5 green hair and white eyes : 1 black hair and white eyes : 1 green hair and red eyes. Which of these explanations accounts for this ratio?
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Question 55
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The following distribution of offspring was observed:
blue wings, green eyes 1,070
blue wings, black eyes 177
red wings, green eyes 180
red wings, black eyes 1,072
In a particular species of mammal, blue wings (B) are dominant to red wings (b), and green eyes (G) are dominant to black eyes (g). Based on these data, what is the recombination frequency?
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Question 56
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Sturtevant's genetic mapping _____.
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Question 57
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The crossover percentage between two different genes is _____.
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Question 58
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The Y chromosomes of mammals contain genes that code for _____.
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Question 59
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Gene R is an X-linked recessive allele in fruit flies that controls wing formation. A cross is performed between two fruit flies where the male is XRY and the female is XRXr. What percentage of the offspring are female with abnormal wing development?
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Question 60
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Hemophilia appears rarely in females. This is because _____.
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Question 61
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We can make connections to our ancestry by analyzing the _____ in males.
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