Sperm can be collected and frozen and are still viable, even if thawed several years later

A researcher is describing a theory of the interaction of genes and the environment on intelligence and uses the term "reaction range." Which of the following is an example of this concept?

a. The effects of environment occur only at the lower ends of the distribution of intelligence scores. b. An individual who may have genes for lower IQ can reach a higher level of intelligence in an enriched environment. c. Psychologists are developing new tests of intellectual functioning that are thought to be more culture-free than previous tests. d. There is a very specific level of intelligence that can be affected by genetic factors; the rest is the result of the environment.

During middle school, social relationships among students:

remain as stable as they were in elementary school. flourish due to the increased number of students. deteriorate due to the increased number of students. become secondary to academics.