Question

a substance that speeds up a chemical reaction without being changed itself
○ carbohydrate
○ catalyst
○ cell
○ cell cycle

Explanation:

• Carbohydrate: A type of organic compound, not related to speeding up reactions.
• Catalyst: By definition, a substance that increases reaction rate without being altered.
• Cell: The basic unit of life, not related to reaction speed.
• Cell cycle: The process of cell growth and division, not related to reactions.

Answer:

B. catalyst