1. Glands that release hormones directly into the bloodstream without ducts are called:

A. Exocrine glands
B. Endocrine glands
C. Apocrine glands
D. Merocrine glands

Correct answer: B

Rationale: The correct answer is B: Endocrine glands. Endocrine glands are specialized glands that release hormones directly into the bloodstream, which then travel to target organs or tissues to regulate various physiological processes. Unlike exocrine glands (choice A), which secrete their products through ducts to specific locations, endocrine glands secrete hormones into the blood for more widespread and systemic effects. Apocrine glands (choice C) release a portion of their cell contents along with the secretions, while merocrine glands (choice D) release their products through exocytosis without any loss of cell material. Therefore, in this case, endocrine glands best describe the glands that release hormones directly into the bloodstream without ducts.

2. The energy released during a chemical reaction is called:

A. Kinetic energy
B. Potential energy
C. Heat energy
D. Exothermic energy

Correct answer: D

Rationale: Exothermic means "outward heat," indicating energy is released during the reaction.

3. What is the mass number of an element?

A. The number of protons in an atom's nucleus.
B. The number of neutrons in an atom's nucleus.
C. The number of electrons in an atom's valence shell.
D. The number of isotopes of an element.

Correct answer: B

Rationale: The mass number of an element is the total number of protons and neutrons in the nucleus of an atom. It is represented by the symbol A and is written as a superscript to the element's symbol. For example, the mass number of carbon-12 is 12, which means that a carbon-12 atom has 6 protons and 6 neutrons in its nucleus.

4. The property of a substance that resists a change in its shape is called:

A. Density
B. Mass
C. Inertia
D. Elasticity

Correct answer: D

Rationale: Elasticity - This refers to a material's ability to resist deformation and return to its original shape after stress is applied. Density, mass, and inertia are related to the substance itself, while viscosity reflects resistance to flow, not shape change.

5. When referring to blood vessel walls, the term "atherosclerosis" describes:

A. The normal process of blood vessel wall thickening with age.
B. The inflammation of the inner lining of blood vessels.
C. The dilation and weakening of a blood vessel wall (aneurysm).
D. The abnormal buildup of plaque within the arterial walls.

Correct answer: D

Rationale: Atherosclerosis is a condition characterized by the abnormal buildup of plaque within the arterial walls. This plaque is made up of substances like cholesterol, calcium, and fatty compounds. Over time, this plaque can harden and narrow the arteries, leading to reduced blood flow and potential complications like heart attacks and strokes. Options A, B, and C do not accurately describe atherosclerosis. Option A is incorrect because atherosclerosis is not a normal aging process but rather a disease. Option B is incorrect because atherosclerosis involves the buildup of plaque rather than inflammation of the inner lining of blood vessels. Option C is incorrect because an aneurysm is a different condition involving the dilation and weakening of a blood vessel wall, not the buildup of plaque seen in atherosclerosis.