This fossil trilobite and this living blue crab both have a limb structure called a biramous limb. What best explains why both species have biramous limbs? A. It is impossible to say. Fossils are very old, so we cannot make observations of the trilobite's ancestors, and we cannot explain its body structures. B. The trilobite and blue crab both share the same ancestor population that had a biramous limb. They inherited this structure from the ancestor population. C. All species have their own specific body structures, so it is a coincidence that this trilobite and blue crab each happen to have the biramous limb structure. D. The trilobite and blue crab are different species, so they must not share an ancestor population. They inherited their biramous limb structure from separate ancestor populations. HELP

All but one describes an effect of aging on the digestive system. a) decreased acid secretion b) decreased elasticity of stomach c) capacity to resist damage decreases d) food remains in stomach for less time

Awire-hair terrier and a smooth-hair terrier are mated. the offspring produced are 6 wire-hair puppies and 2 smooth-hair puppies. a. what pattern of inheritance best describes this situation? b. what is the genotype(s) of the wire-haired puppies? of the smooth-haired puppies? c. what would be the expected genotype and phenotype ratios of a mating between 2 wire-haired terriers that are heterozygous?

Awoman whose sister tested positive for a specific mutation in the brca1 gene, which increases the risk for breast and ovarian cancer, is found not to have that mutation but does have a mutation of unknown significance near the known mutation site. how should this woman be counseled? select one: a. she should be informed that her risk for breast cancer is greater than the general population but not as great as her sister’s risk. b. she should be informed that because she does not have the mutation, her risk for breast cancer is not greater than that of the general population. c. she should be informed of her gene mutation status and be presented with all the available prophylaxis options and reconstruction options. d. she should be informed that she does not have the specific mutation but that because another mutation is present she should be vigilant about screening