Why are photosynthetic organisms found only near the surface of the oceanic zone

All individuals have two alleles for a given trait. according to mendel's these alleles are passed down one each from both mother and father.

Which blood cell spend most of their time in the lymphatic system?

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.