During which period did the presence of stromatolites decline?

Which of the following occurs after a natural or unnatural disturbance in an ecosystem

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.

Aheterozygous normal male marries a woman with a sickle cell anemia. give the genotypes and possible phenotypes of the offspring