A substance that speeds up the rate of chemical reactions is called

It is a catalyst.

Explanation:

A catalyst provides an alternative route for the reaction with a lower activation energy. Some catalysts in chemistry are platinum, nickel, and manganese oxide.

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the supermassive black hole is in the middle of the galaxy.

well for one plants are always the producer, so a is the answer. a wolf is more of the consumer(predator) and the deer is the prey so i know those two are out of the question. also mushrooms are fungi/fungus so a is the producer.