The covalent bonds between the monomers of an enzyme macromolecule are:

The correct answer is c. 100,000. The pH scale is a logarithmic scale, which means that each change of one pH unit represents a tenfold change in the hydrogen-ion concentration. A pH 4 solution has a hydrogen-ion concentration that is 10^5 (or 100,000) times greater than that of a pH 9 solution.

a. 0.00001 is the hydrogen-ion concentration of a pH 9 solution as compared with a pH 4 solution.

b. 5 is the difference in pH units between a pH 4 solution and a pH 9 solution.

d. 50 is not the correct answer.

The correct answer is c. Atoms, cells, tissues, organs. This is the correct order of structures from simple to complex. Atoms are the smallest and simplest units of mater. Cells are made up of atoms and are the basic units of life.

Tissues are groups of similar cells that work together to perform a specific function. Organs are made up of different types of tissues and perform more complex functions.

A. Cells, tissues, atoms, organs is not the correct order from simple to complex.

B. Atoms, organs, tissues, cells is not the correct order from simple to complex.

D. Organs, tissues, cells, atoms is not the correct order from simple to complex.

The best reason for the prolonged preservation of the body is that it was frozen in the cold temperature of the Alps shortly after death and remained frozen until it was found. Freezing can preserve a body by slowing down or stopping the decomposition process.

The other options are not as likely to have caused prolonged preservation.

Ultraviolet rays can damage molecules rather than preserve them. Toxins in food would not necessarily kill all bacteria that could cause decomposition. Blood loss from an arrow wound would not necessarily clear all enzymes that could break down tissue.

Emphysema is a lung condition that is caused by damage to the alveoli, the tiny air sacs in the lungs where gas exchange occurs. When the alveoli are damaged, the body has difficulty exchanging oxygen and carbon dioxide. This can lead to shortness of breath and other respiratory problems. The other options are not directly related to the function of the alveoli or the effects of emphysema.

The correct answer is c. Fibrinogen. Fibrinogen is a protein present in blood plasma that plays a key role in blood clotting. When an injury occurs and bleeding begins, fibrinogen is converted into fibrin, which forms a mesh-like structure that helps to trap blood cells and form a clot.

A. Monocytes are a type of white blood cell, not a protein present in blood plasma.

B. Platelets are cell fragments that play a role in blood clotting, but they are not a protein present in blood plasma.

D. Lymphocytes are a type of white blood cell, not a protein present in blood plasma.

The apocrine gland is a component of the integumentary system that secretes pheromones. Pheromones are chemical signals that are released by an individual and can affect the behavior or physiology of other individuals of the same species.

The other options are not components of the integumentary system that secrete pheromones. The fossa ovalis is a depression in the interatrial septum of the heart, the seminiferous tubule is a structure in the testes where sperm are produced, and the dermal papilla is a structure at the base of a hair follicle that provides nutrients to the hair.

When a muscle cell is stimulated by a nerve impulse, calcium ions are released from the sarcoplasmic reticulum into the cytoplasm. The calcium ions bind to the troponin complex, which is a protein that regulates the interaction between actin and myosin filaments. The binding of calcium to troponin causes a conformational change that exposes the binding sites for myosin on the actin filaments. This allows the myosin heads to attach to the actin and pull the filaments past each other, resulting in muscle contraction.

The parotid gland is an exocrine gland that secretes saliva into the mouth. Exocrine glands secrete their products into ducts that carry the secretions to the body's surface or into body cavities. The other options are endocrine glands, which secrete hormones directly into the bloodstream. The pineal gland secretes melatonin, the parathyroid glands secrete parathyroid hormone, and the pituitary gland secretes several hormones that regulate various bodily functions.

The correct answer is d. A substance with a pH of 3 is 10 times more acidic than a substance with a pH of 4. The pH scale is a logarithmic scale, which means that each change of one pH unit represents a tenfold change in the hydrogen-ion concentration. A substance with a pH of 3 has a hydrogen-ion concentration that is 10 times greater than that of a substance with a pH of 4.

A. A substance with a pH of 3 is not two times more alkaline than a substance with a pH of 4.

B. A substance with a pH of 3 is not 10 times more alkaline than a substance with a pH of 4.

C. A substance with a pH of 3 is not two times more acidic than a substance with a pH of 4.

The thylakoid membrane of chloroplasts is where the light-dependent reactions of photosynthesis take place, while the mitochondrial inner membrane is where the electron transport chain and ATP synthesis occur during cellular respiration.

The tonoplast is the membrane that surrounds the central vacuole in plant cells. It is not involved in cellular respiration or photosynthesis.

The other options, epithelial and nuclear, are not related to these processes.