A healthy ecosystem contains a diverse variety of species that factor into the food web within the ecosystem. It also has varied individuals within each population. Which of the following helps to keep an ecosystem diverse?
o A
increasing population density
B
interactions among communities
с
biotic factors
D
genetic variation

Describe the response the kidneys have to dehydration and excessive water intake. what happens to the concentration of urine in each case ?

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures

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.