Allele, gene, chromosome and then nucleus
Enzymes are usually very specific as to which reactions they catalyze and the substrates that are involved in these reactions. The enzyme and the substrate possess specific complementary geometric shapes that fit exactly into one another. This is often referred to as "the lock and key" model.
Answer: D. All of the above
Explanation: If airplane, air pollution. If boat, oil spills. They need to clear trees and stuff for airplanes and boats, so that's habitat loss. So you're answer would be D. All of the above
Mechanical waves cannot move without a medium
