(Q).
Q: What is often the cause of phenotypic differences between identical twins? Read this paragraph and choose the correct option from the provided answers: Scientists often study the effects of environment on phenotype by studying identical twins. Identical twins have the same genes, so phenotypic differences between twins often have an environmental cause. Twin studies help understand the relative importance of environmental and genetic influences on individual traits and behaviors. Twins are a valuable source of information concerning the relationship between genes and environment. As monozygotic twins (identical) share their nuclear DNA, their polymorphisms , the nucleotide differences that make their DNA unique, are common to the two individuals. This means that any phenotypic variation, such as in height, intelligence, or any other measurable trait, is due to the environment. What is different about the experiences of the twins? What unique experiences might one twin have that the other twin did not have? By comparing phenotypes of hundreds of twins, researchers can understand the roles of genetics, shared environment and unique experiences in the formation and development of specific traits. Choices: - natural selection - genetics - learned behavior - environment A:
(A).
environment

(Q).
Q: As the atoms approach one another, their electron clouds gradually begin to do what? Read this paragraph and choose the correct option from the provided answers: As the atoms approach one another, their electron clouds gradually begin to overlap. Now there are several interactions which begin to occur. One is that the single electrons that each hydrogen atom possesses begin to repel each other. This repulsive force would tend to make the potential energy of the system increase. However, the electron of each atom begins to be attracted to the nucleus of the other atom. This attractive force tends to make the potential energy of the system decrease. Choices: - magnetize - shrink - disappear - overlap A:
(A).
overlap

(Q).
Q: Like acetic acid, pentanoic acid is what kind of acid? Read this paragraph and choose the correct option from the provided answers: Like acetic acid, pentanoic acid is a carboxylic acid. Unlike acetic acid, however, the alkyl group is rather large, consisting of a 4-carbon chain as in butanol. As with butanol, the nonpolar character of the alkyl group is likely to be as important as the polar character of the carboxylic acid group, making it unlikely that pentanoic. Choices: - hydroxyl - carbonic - amino - carboxylic A:
(A).
carboxylic