Genetic studies of an animal show that eye color is controlled by an autosomal gene with the dominant allele (R) for
red eye color and the recessive allele (r) for yellow eye color. A second autosomal gene has the dominant allele (T) for
paws with thumbs and the recessive allele (t) for paws without thumbs. The genetic cross RRTT x rrtt creates offspring
with genotype RrTt. One of those dihybrids is mated in a testcross (RrTt x rrtt). If the two genes are completely linked (no
recombination occurs between them), then the testcross should produce offspring with the phenotype ratio ____.
a. 3 red-eyed with thumbs : 1 yellow-eyed without thumbs.
b. 1 red-eyed with thumbs : 1 yellow-eyed with thumbs: 1 red-eyed without thumbs: 1 yellow-eyed without
thumbs.
c. 1 red-eyed with thumbs : 1 yellow-eyed without thumbs.
d. 9 red-eyed with thumbs : 3 yellow-eyed with thumbs: 3 red-eyed without thumbs: 1 yellow-eyed without
thumbs.
e. 1 yellow-eyed with thumbs : 1 red-eyed without thumbs.
ANSWER: c
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A. They possess many different enzymes and they can reproduce independently of living cells but only at a slow rate. B. They possess many different enzymes. C. They can reproduce independently of living cells but only at a slow rate. D. They behave as a macromolecular complex and are no more alive than are ribosomes.
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The most successful mammals belong to the marsupials group.
Answer the following statement true (T) or false (F)
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A) inactivates interferons. B) increases vasodilation, contributing to inflammation. C) increases sweating and consequently the barrier effect. D) prevents viral infection of fibroblasts. E) increases the effectiveness of interferons and phagocytes.