Which of the following substances is excreted by sweat glands in response to the breakdown of proteins and the formation of ammonia?

a. Water boils to produce steam at 100°C - This is a phase change (from liquid to gas) and not a chemical reaction of water.

b. Water dissolves sugar - This is a physical change, not a chemical reaction of water.

c. Water produces gas with sodium metal - This reaction involves the chemical reaction of water with sodium metal to produce hydrogen gas.

d. Water and oil separate when combined - This is a physical separation, not a chemical reaction of water.

Biological macromolecules are large organic molecules such as carbohydrates, lipids, nucleic acids, and proteins. They are built from smaller molecules, which are linked commonly by covalent bonds, and these can be broken down.

The parathyroid hormone (PTH) from the parathyroid glands is important in serum calcium regulation. It increases blood calcium levels by stimulating osteoclasts to break down bone and release calcium into the bloodstream. PTH also enhances the absorption of calcium from the intestines and the kidneys.

Exocrine glands secrete their products into ducts that carry them to the target organs. In contrast, endocrine glands secrete their products directly into the bloodstream, which carries them to target cells throughout the body.

Conducting the experiment with half the women taking water and the other half taking an energy drink creates a study and experimental group, which can allow for comparison and conclusion. The researchers can compare the effects of the energy drink directly with a baseline, and this helps to establish a cause-and-effect relationship and provides stronger evidence to support their conclusion.

ATP is produced by a series of reactions that occur in the mitochondria. The mitochondria have a double membrane structure, with an inner membrane that is folded into cristae. These cristae contain the enzymes and proteins that are involved in the process of cellular respiration, which converts glucose and oxygen into ATP and carbon dioxide.

This means that a hypothesis is considered valid until it is disproved by experimental evidence. However, even if a hypothesis has not been falsified, it is still considered provisional and subject to further testing and scrutiny.

Cardiac muscles have intercalated discs that enable them to contract in a coordinated manner. Skeletal muscles do not have intercalated discs, as their contraction is under voluntary control and does not require the same level of synchronization seen in the involuntary contraction of cardiac muscle.

The digestive system breaks down complex food substances into small and less complex absorbable compounds. Proteins, for instance, are broken down to constituent amino acids through a digestion process that combines mastication and enzymatic breakdown.