Two of the following statements are false. Circle the letter and fix the statement to make it true. a. Enzymes are NOT used up by a chemical reaction
b. Enzymes help to speed up chemical reactions
c. Enzymes are made up of proteins
d. Enzymes are needed for a chemical reaction to occur.

Which of the following best describes the expensive tissue hypothesis? brains require more energy, so the gut had to be reduced, and larger brains and tool use led to higher quality diets. increasing body size means that homo neanderthalensis had to include more fat in its diet. brains require more energy, so the gut had to be reduced as brains got bigger. brains require more fat, so the gastrointestinal viscera (gut) had to expand, and hands were needed to acquire more food.