Fish die more in summer due to oxygen depletion which refers to low levels of dissolved oxygen (DO) in water. Warm water is much less capable of holding oxygen gas in solution than cool water. For example, water that is 90° F can only hold 7.4 mg/L DO at saturation, whereas water that is 45° F can hold 11.9 mg/L DO at saturation. This physical phenomenon puts the fish in double jeopardy because at high water temperatures their metabolic rates increase, hence their physiologic demand for oxygen increases.

Correct Option: C

Fish die more in summer due to oxygen depletion which refers to low levels of dissolved oxygen (DO) in water. Warm water is much less capable of holding oxygen gas in solution than cool water. For example, water that is 90° F can only hold 7.4 mg/L DO at saturation, whereas water that is 45° F can hold 11.9 mg/L DO at saturation. This physical phenomenon puts the fish in double jeopardy because at high water temperatures their metabolic rates increase, hence their physiologic demand for oxygen increases.

Enzymes are in general globular proteins and range from just 62 amino acid residues in size, for the monomer of 4-oxalocrotonate tautomerase, to over 2,500 residues in the animal fatty acid synthase. The activities of enzymes are determined by their three-dimensional structure.

Correct Option: C

Enzymes are in general globular proteins and range from just 62 amino acid residues in size, for the monomer of 4-oxalocrotonate tautomerase, to over 2,500 residues in the animal fatty acid synthase. The activities of enzymes are determined by their three-dimensional structure.

Metabolism is the sum total of chemical reactions occurring in cells. It includes both anabolism, the synthesis of the biomolecules (e.g., protein synthesis, DNA replication, glucose synthesis in plants) and catabolism, the degradation of molecules usually for the production of energy (e.g., glycolysis, Krebs Cycle). Metabolism is carried out by specific enzymes which catalyze each step of a long series of reactions.

Correct Option: C

Metabolism is the sum total of chemical reactions occurring in cells. It includes both anabolism, the synthesis of the biomolecules (e.g., protein synthesis, DNA replication, glucose synthesis in plants) and catabolism, the degradation of molecules usually for the production of energy (e.g., glycolysis, Krebs Cycle). Metabolism is carried out by specific enzymes which catalyze each step of a long series of reactions.

The average heart rate for adult humans is about 70 to 75 beats per minute in a normal relaxed mode. The "normal" heart beat rate is taken to be "72 beats per minute.”

Correct Option: C

The average heart rate for adult humans is about 70 to 75 beats per minute in a normal relaxed mode. The "normal" heart beat rate is taken to be "72 beats per minute.”

Decay is an essential life process, which helps to digest food and recycle materials. Bacteria and fungi are the main groups of decomposer. They release enzymes to break down compounds, so that they can absorb the nutrients. Organisms that feed on dead material in this way are called saprophytes.

Correct Option: B

Decay is an essential life process, which helps to digest food and recycle materials. Bacteria and fungi are the main groups of decomposer. They release enzymes to break down compounds, so that they can absorb the nutrients. Organisms that feed on dead material in this way are called saprophytes.