John has periods during the night where he stops breathing, causing carbon dioxide levels in his blood to rise. Once the levels get too high, he wakes up, gasping for breath. John suffers from:

Chromosomes are threadlike structures made of

A) serotonin molecules B) epigenetic molecules C) dna molecules D) dizygotic molecules

When culture is used as an independent variable in research, the research is not truly

experimental because a. cultural differences are too complex to be studied experimentally. b. ethical considerations prevent experimentation on cultural groups. c. subjects are not randomly assigned to a cultural group. d. biological influences cannot be separated from cultural influences. e. matching of subjects is necessary.