1. Which type of muscle is characterized by involuntary contractions, is striated, and is primarily found in the heart?

A. Skeletal muscle
B. Smooth muscle
C. Cardiac muscle
D. Elastic muscle

Correct answer: C

Rationale: The correct answer is C: Cardiac muscle. Cardiac muscle is characterized by involuntary contractions, meaning it contracts without conscious control. It is striated, which refers to the striped appearance of muscle fibers under a microscope. Cardiac muscle is primarily found in the heart, where it plays a crucial role in pumping blood throughout the body. Skeletal muscle (option A) is also striated but is under voluntary control. Smooth muscle (option B) is non-striated and found in organs like the intestines. Elastic muscle (option D) is not a recognized type of muscle tissue.

2. Which element is used in insulin and promotes glucose uptake into cells for energy production?

A. Zinc
B. Chromium
C. Manganese
D. Iron

Correct answer: B

Rationale: Chromium aids in insulin's function, enhancing glucose uptake by cells and regulating blood sugar levels.

3. The number of protons in the nucleus of an atom determines its:

A. Mass number
B. Atomic number
C. Isotope
D. Valence electron count

Correct answer: B

Rationale: The atomic number (Z) equals the number of protons in the nucleus and uniquely identifies an element. Mass number (A) includes both protons and neutrons, isotopes have different neutron numbers, and valence electrons are involved in bonding, not atomic identity.

4. The phenomenon responsible for the creation of rainbows is:

A. Reflection only
B. Diffraction
C. Refraction and reflection
D. Polarization

Correct answer: C

Rationale: The correct answer is C: Refraction and reflection. Rainbows are formed when sunlight is refracted and reflected inside raindrops. The sunlight entering the raindrop is refracted, then internally reflected off the back surface of the droplet, and finally refracted again as it exits the droplet. This dispersion of light causes the separation of colors we see in a rainbow. Reflection alone (option A) does not account for the formation of rainbows. Diffraction (option B) is the bending of light around obstacles, not the main mechanism behind rainbows. Polarization (option D) refers to the orientation of light waves, which is not the primary process involved in creating rainbows.

5. Which of the following numbers is NOT divisible by 3?

A. 105
B. 141
C. 273
D. 810

Correct answer: D

Rationale: Rationale: To determine if a number is divisible by 3, we can check if the sum of its digits is divisible by 3. If the sum of the digits is divisible by 3, then the original number is also divisible by 3. A) 105: 1 + 0 + 5 = 6, which is divisible by 3. Therefore, 105 is divisible by 3. B) 141: 1 + 4 + 1 = 6, which is divisible by 3. Therefore, 141 is divisible by 3. C) 273: 2 + 7 + 3 = 12, which is divisible by 3. Therefore, 273 is divisible by 3. D) 810: 8 + 1 + 0 = 9, which is divisible by 3. Therefore, 810 is divisible by 3. Since all the

6. Which of the following terms refers to a muscle twitch, a single forceful contraction of a muscle fiber?

A. Tetanus
B. Trembling
C. Fasciculation
D. Rigidity

Correct answer: C

Rationale: The correct answer is C: "Fasciculation." A muscle twitch refers to the involuntary contraction of a small group of muscle fibers. Tetanus (choice A) is a sustained contraction of a muscle caused by rapid stimulation. Trembling (choice B) is the shaking or quivering of muscles. Rigidity (choice D) refers to stiffness or inflexibility in muscles. Fasciculation is the term that specifically describes a muscle twitch, which is a single forceful contraction of a muscle fiber. Therefore, choice C is the most appropriate term for this scenario.