Hiv attacks which of the following cells in the human body a) the cells of the liver b) bacterial cells invading the body c) the cells of the immune system d) the cells of the mucous membranes

The following image is of a diatom. it lives in water and gets food from photosynthesis. it is encased in a hard shell made of something similar to glass or sand . a diatom is a(n) because it has a) multi-celled organism; specialized parts. b) vertebrate; a skeleton. c) insect; an exoskeleton. d) single-called organism; only one cell.

What sentence best supports the statement that hormones are involved in the regulation of homeostasis? a. the hormone erythropoeitin increases the production of red blood cells when oxygen levels are low. b. the hormone oxytocin promotes labor contractions of the uterus during childbirth. c. the hormone melatonin induces sleep and its production is slowed by exposure to light. d. the hormone cortisol suppresses the immune system and is produced when the body is under stress.

When the cell concentrates potassium within, against the natural tendency of matter, it is performing a.passive diffusion b.facilitated diffusion c.active transport d.pinocytosis