1. The peripheral nervous system can be further divided into which two main parts?

A. Sensory and motor
B. Sympathetic and parasympathetic
C. Myelinated and unmyelinated
D. Central and peripheral

Correct answer: A

Rationale: The correct answer is A: 'Sensory and motor.' The peripheral nervous system is divided into two main parts based on their functions. The sensory division (afferent) transmits sensory information from receptors to the central nervous system, while the motor division (efferent) transmits signals from the central nervous system to muscles and glands to produce a response. Options B, C, and D are incorrect as they do not accurately describe the main divisions of the peripheral nervous system. Understanding this division is crucial in comprehending how information is processed and responses are generated in the body.

2. What is the difference between a pure substance and a mixture?

A. Pure substances have fixed composition, mixtures don't.
B. Mixtures have fixed composition, pure substances don't
C. Pure substances are always solids, mixtures can be any state
D. Pure substances are always elements, mixtures are always compounds

Correct answer: A

Rationale: Rationale: - Pure substances have a definite and constant composition, meaning they are made up of only one type of atom or molecule. This composition does not vary. - Mixtures, on the other hand, are composed of two or more substances physically combined. The components of a mixture can be present in varying proportions, leading to a variable composition. - Option A correctly distinguishes between pure substances and mixtures based on the fixed composition of pure substances and the variable composition of mixtures.

3. Which structure in the heart is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

A. Aortic valve
B. Pulmonary valve
C. Tricuspid valve
D. Mitral valve

Correct answer: D

Rationale: The correct answer is D, the Mitral valve. The Mitral valve, also known as the bicuspid valve, is located between the left atrium and left ventricle in the heart. It consists of two cusps that close tightly when the left ventricle contracts, preventing the backflow of blood into the left atrium. The aortic valve (option A) is responsible for preventing the backflow of blood from the aorta into the left ventricle, not the left atrium. The pulmonary valve (option B) prevents backflow from the pulmonary artery into the right ventricle, and the tricuspid valve (option C) prevents backflow from the right ventricle into the right atrium. Therefore, the Mitral valve is specifically responsible for preventing backflow from the left ventricle into the left atrium.

4. A ball is thrown horizontally off a cliff with a speed of 10 m/s. What is the horizontal distance the ball travels before hitting the ground?

A. 10 m
B. 20m
C. 30m
D. Cannot be determined without knowing the height of the cliff

Correct answer: C

Rationale: When a ball is thrown horizontally, its horizontal velocity remains constant throughout its motion. The time taken to hit the ground is determined by the vertical motion, which is independent of the horizontal velocity. Therefore, the horizontal distance traveled by the ball is determined by the horizontal velocity and the time taken to hit the ground. In this case, the horizontal distance is calculated as distance = velocity × time = 10 m/s × time. Since the horizontal velocity is 10 m/s and the time taken to hit the ground is determined by the vertical motion, the horizontal distance traveled by the ball is 10 m/s × time. Without knowing the height of the cliff, we can still determine the horizontal distance traveled by the ball, which is 10 m/s × time.

5. Which digestive enzyme is primarily responsible for breaking down proteins?

A. Pepsin
B. Lipase
C. Amylase
D. Maltase

Correct answer: A

Rationale: The correct answer is A: Pepsin. Pepsin is primarily responsible for breaking down proteins in the stomach. It is an enzyme produced by the gastric chief cells in the stomach lining and works in a highly acidic environment to break down proteins into smaller peptide fragments. Lipase, on the other hand, is responsible for breaking down fats, amylase for breaking down carbohydrates, and maltase for breaking down maltose (a type of sugar). Therefore, pepsin is the correct enzyme involved in the digestion of proteins.