When people put on weight, their fat cells release a substance, which is carried in the bloodstream to the brain, where it will tell us to eat less. This substance is

Emily's child has facial deformities and displays some mental impairment. If these defects can be traced to a teratogen used by Emily when she was pregnant, which was she most likely abusing?

a) nicotine b) cocaine c) marijuana d) alcohol

Studies of heritability in humans that assume that if genes influence a certain trait, close relatives should be more similar with that trait than distant relatives are called ________ studies

a. strain b. selection c. family d. twin