The persistence of the sickle-cell anemia allele
in the African population is the result of
a. a high rate of mutation of the normal allele
to the sickle-cell anemia allele.
b. the advantage of the heterozygous form
over the homozygous forms.
c. nonrandom mating.
d. a decline in the occurrence of malaria in
Africa.
e. genetic drift.
B
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Suppose you have identified a type of lizard that seems to have acquired a mutation in which hindlimbs are absent. Which gene, also responsible for the loss of limbs in snake, may be mutated in this animal?
A) Bicoid B) MONOPTEROS C) PHANTASTICA D) Cytoplasmic deteminants E) Sonic Hedgehog
Mycorrhizae are especially effective in helping plant roots uptake
A. nitrogen. B. phosphorus. C. potassium. D. iron. E. magnesium.
How do organisms help to cause the changes that result in their own replacement in succession?
What will be an ideal response?
One difference between cell division in plant cells and in animal cells is that plant cells have
A) centrioles. B) centromeres. C) a cell plate. D) chromatin.