What allows reactions to take place to take place at a normal body temperature?
a enzymes add additional energy to chemical reactions.
b carbohydrates provide additional energy for body cells.
c lipids store extra energy that can be used in reactions.
d. enzymes reduce activation energy required for reactions.

Which of the following best describes the purpose of the parathyroid hormone? a. it decreases the blood calcium level and decreases blood phosphorus level. b. it decreases the blood calcium level and increases the blood phosphorus level. c. it increases the blood calcium level and increases blood phosphorus level. d. it increases the blood calcium level and decreases blood phosphorus level.

Can an organism fill more than one trophic level?

Through wich tissue do sugar get transported to reach the leaves during growth and reproduction