You are studying body color in an African spider and have found that it is controlled by a single gene with four alleles: B (brown), br (red), bg (green), and by (yellow). B is dominant to all the other alleles, and by is recessive to all the other alleles. The bg allele is dominant to by but recessive to br. You cross a brown (B/by) spider with a pure-breeding green spider. Predict the phenotype of the progeny.
A. all yellow
B. half brown, half green
C. three-fourths brown, one-fourth green
D. all brown
E. all green
Ans: B. half brown, half green
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Answer the following statements true (T) or false (F)
1. Roots have axillary buds that allow for the development of lateral or branch roots. 2. Mature bean seeds have starch stored in their endosperm. 3. Corn seeds have one embryonic seed leaf (cotyledon). 4. Flowers demonstrate indeterminate growth.
The critical tissue for producing a vasodilatory effect of acetylcholine in Robert Furchgott's experiments with rabbit aortas was the
A. endothelium. B. smooth muscle layer. C. elastic outer layer. D. pericardium. E. one-way valves.
Parenchyma ground tissue is the site of photosynthesis
a. True b. False
Mendel accounted for the observation that traits that had disappeared in the F1 generation reappeared in the F2 generation by proposing that _____
A) new mutations were frequently generated in the F2 progeny, "reinventing" traits that had been lost in the F1 B) the mechanism controlling the appearance of traits was different between the F1 and the F2 plants C) traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1 D) members of the F1 generation had only one allele for each trait, but members of the F2 had two alleles for each trait