A. They impede fish migration and spawning
Answer:
objective lenses
Explanation:
objective lenses with different magnifications, screwed into a circular "nosepiece" which may be rotated to select the required lens.
Answer:
Enzymes are catalysts for chemical reactions in living things. Enzymes, like other catalysts, lower the activation energy and increase the rate of chemical reac- tions. ... This means that enzymes do not change the direction of a reaction— they just change the amount of time needed for equilibrium to be reached.
Explanation:
