How is the level of oxytocin controlled by a positive-feedback mechanism?
a. the oxytocin in blood stimulates the pituitary to maintain the same level of oxytocin.
b. the oxytocin in blood stimulates the pituitary to secrete more oxytocin.
c. the oxytocin in blood stimulates the pituitary to secrete less oxytocin

Which of the following particles always has a positive charge? a. electronb. neutron c. proton d. ion

Amino acids contain the elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. of the 20 amino acids found in humans, 11 are called "nonessential" because they can be manufactured by the body when needed. which elements in these 11 amino acids are commonly obtained from the metabolism of sugar molecules?

Ascientist is conducting an investigation that involves water, silver, carbon dioxide, and oxygen gas which group of statements best describes all of the materials he is using in the investigation?