Lactase and carbonic anhydrase are examples of what type of substance?
a. substrate
b. reactant
c. product
d. enzyme

Lactase and carbonic anhydrase are examples of an enzyme. Enzyme by definition, is a chemical substance in plants and animals that helps in causing natural process. Lactase is an enzyme that hydrolyzes galactosides and occurs in intestines of young mammals and in yeasts.

because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). they locate the types of rock that are likely to contain natural gas deposits.