1. A scientific theory is:

A. A personal belief or hunch about how something works.
B. A well-substantiated explanation based on evidence and repeated testing.
C. A single experiment's findings not yet confirmed by others.
D. A fixed and unchanging dogma beyond questioning.

Correct answer: B

Rationale: Theories in science are constantly evolving and open to revision as new data emerges, unlike personal beliefs or fixed dogmas.

2. The three main types of muscle tissue in the human body are:

A. Smooth, cardiac, and voluntary skeletal
B. Smooth, skeletal, and involuntary cardiac
C. Voluntary smooth, cardiac, and skeletal
D. Striated, non-striated, and epithelial

Correct answer: A

Rationale: The correct answer is A: Smooth, cardiac, and voluntary skeletal. Smooth muscle is found in the walls of internal organs and blood vessels, cardiac muscle makes up the heart, and voluntary skeletal muscle is attached to the bones and responsible for movement. Choice B is incorrect because cardiac muscle is involuntary, not voluntary. Choice C is incorrect because smooth muscle and cardiac muscle are involuntary, not voluntary. Choice D is incorrect because 'striated' and 'non-striated' refer to the appearance of muscle fibers, not the main types of muscle tissue in the body.

3. Which organ helps break down food by grinding it with your teeth?

A. Stomach
B. Esophagus
C. Liver
D. Mouth

Correct answer: D

Rationale: Rationale: The mouth is the organ that helps break down food by grinding it with your teeth. The process of chewing, also known as mastication, breaks down food into smaller pieces, making it easier to swallow and digest. The teeth in the mouth play a crucial role in this initial stage of digestion by physically breaking down food into smaller particles. The other options listed do not directly participate in the mechanical breakdown of food through chewing.

4. The energy absorbed during a chemical reaction is called:

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

Correct answer: D

Rationale: Endothermic means "inward heat," indicating energy is absorbed during the reaction.

5. Adipose tissue, also known as fat, serves multiple functions. Which of these is NOT a function of adipose tissue?

A. Insulation
B. Energy storage
C. Hormone production
D. Muscle movement

Correct answer: D

Rationale: Adipose tissue plays various essential roles in the body, including insulation to help regulate body temperature, energy storage by storing excess energy in the form of fat, and hormone production such as leptin and adiponectin. However, adipose tissue is not directly responsible for muscle movement. Muscles are primarily responsible for movement, while adipose tissue provides cushioning and support around organs. Therefore, option D, 'Muscle movement,' is the correct answer as it does not align with the functions of adipose tissue.