"runner's high" occurs when prolonged, intense athletic activity causes the release of the brain's natural painkiller.

For each of the following, decide whether the statement describes photosynthesis, cellular respiration, or both. releases energy in the form of atp. stores energy in glucose molecules. performed by producers. performed by consumers.

Living cells cannot use heat to provide the activation energy for biochemical reactions because which choice(s) complete the sentence correctly? a) answer choice ii. eliminate b) answer choices ii and iv. c) answer choice iii and iv. d) all answers can complete the sentence.

Which of the following would be a body response when stepping outside without a coat on a snowy day? a. senaceous glands. secrete more senum b. more liquid is transported by the body to the skin fir insulation c. blood vessels in the skin narrow and contract d. blood vessels in the skin expand