21.
upwelling is a process where water moves from deeper parts of the sea to the surface.
this water contains a lot of nutrients from the remains of dead organisms.
(a)
(i)
nitrates and phosphates are two of these nutrients. they provide a source of
nitrogen and phosphorus for cells.
give a biological molecule that contains:
1. nitrogen
2. phosphorus

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.

Which of the following is a common response to cell signaling?

Modern sea star larvae resemble some primitive vertebrate larvae. this similarity may suggest that primitive vertebrates