Which statement best describes how a catalyst can speed up a chemical reaction? The catalyst decreases the activation energy needed. The catalyst increases the concentration of products. The catalyst binds to enzymes to release substrates. The catalyst increases the concentration of reactants.

the answer is:

carbon dioxide

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

the scientific method.