1. Which organelle is responsible for cellular respiration, producing ATP for energy?

A. Nucleus
B. Mitochondria
C. Golgi apparatus
D. Vacuole

Correct answer: B

Rationale: The correct answer is B: Mitochondria. Mitochondria are known as the powerhouse of the cell because they are responsible for cellular respiration, a process that produces ATP (adenosine triphosphate) for energy. The other organelles listed, such as the nucleus, Golgi apparatus, and vacuole, do not play a direct role in cellular respiration or ATP production. The mitochondria contain specialized structures like cristae and enzymes that carry out the biochemical reactions of cellular respiration, making them essential for energy production in the cell.

2. Which of the following is NOT a common site for lymph nodes?

A. Groin
B. Armpit
C. Neck
D. Liver

Correct answer: D

Rationale: The correct answer is D: 'Liver.' Lymph nodes are small, bean-shaped structures that are part of the lymphatic system. They are commonly found in areas such as the groin, armpit, and neck, where they help filter and trap harmful substances. The liver, while an important organ in the body, does not typically contain lymph nodes. Therefore, it is not a common site for lymph nodes. Understanding the locations of lymph nodes in the body is important for identifying potential sources of infection or cancer when assessing patients.

3. What property of a wave determines the loudness of sound when heard by the human ear?

A. Frequency
B. Amplitude
C. Wavelength
D. Velocity

Correct answer: b

Rationale: The amplitude of a sound wave correlates with its perceived loudness by the human ear.

4. Which of the following statements about prions is TRUE?

A. They are composed of proteins only
B. They are easily destroyed by common disinfectants
C. hey are a type of antibiotic
D. They are a live organism

Correct answer: A

Rationale: Rationale: A) This statement is true. Prions are infectious agents composed entirely of protein, lacking nucleic acids such as DNA or RNA. They are known for causing neurodegenerative diseases in animals and humans. B) This statement is false. Prions are not easily destroyed by common disinfectants due to their unique structure and resistance to conventional sterilization methods. C) This statement is false. Prions are not a type of antibiotic. They are a distinct class of infectious agents. D) This statement is false. Prions are not live organisms but rather misfolded proteins that can induce abnormal folding in normal proteins, leading to disease.

5. A satellite orbits the Earth at constant speed. Which force is responsible for its circular motion?

A. Gravitational force from the Earth
B. Thrust from the satellite's engine
C. Friction between the satellite and the atmosphere
D. Normal force from the Earth's surface

Correct answer: A

Rationale: This force acts towards the Earth's center, providing the centripetal force required for the satellite to move in a circle.

6. What are isotopes?

A. Atoms of the same element with different numbers of protons.
B. Atoms of the same element with different numbers of neutrons.
C. Atoms of different elements with the same number of protons.
D. Atoms of different elements with the same number of electrons.

Correct answer: B

Rationale: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. This means that isotopes have the same atomic number (Z) but different mass numbers (A). For example, carbon-12 (Â¹Â²C), carbon-13 (Â¹Â³C), and carbon-14 (Â¹â´C) are all isotopes of carbon. They all have six protons in their nuclei, but they have different numbers of neutrons: carbon-12 has six neutrons, carbon-13 has seven neutrons, and carbon-14 has eight neutrons.