If a child inherits different forms of a gene from each parent, he or she is said to be ___________ for the trait

During the absolute refractory period, further stimulation, no matter how intense, cannot cause another action potential to be generated

a. true b. false

What percentage of American toddlers were toilet trained by 18 months, according to a study completed in 1957?

a. 2% b. 42% c. 62% d. 92%