Which is a base? a. substance c is formed from the reaction of an acid and a base. b. substance a gives off h+ ions that combine with oh– ions when dissolved in water. c. substance b gives off oh– ions that combine with h+ ions when dissolved in water.

Food contains a sugar called ( ), which is broken down in a process called cellular ( ). this process uses ( ) to break down food molecules and provide energy for cells. fill in the parentheses

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.

How do the sperm cells get from the stigma to the ovules? a. they slide down the petals to the bottom of the flower. b. they travel through pollen tubes. c. they travel along filaments. d. insects carry the sperm cells from the stigma to the ovules.