1. The involuntary reflex arc that withdraws your hand from a hot object involves the:

A. Central nervous system only
B. Peripheral nervous system only
C. Both CNS and PNS
D. Sensory neurons only

Correct answer: C

Rationale: The correct answer is C: 'Both CNS and PNS'. This is because the reflex arc involves both the central nervous system (CNS) and the peripheral nervous system (PNS). The sensory neurons in the PNS detect the stimulus (hot object), then send signals to the spinal cord in the CNS. The spinal cord processes the information and immediately sends a motor response signal back out through the PNS to move the hand away from the hot object. This rapid and involuntary response demonstrates the coordination between the CNS and PNS in executing the reflex arc.

2. What is the name for the smallest amount of an element that can exist independently and retain its chemical properties?

A. Molecule
B. Atom
C. Compound
D. Mixture

Correct answer: A

Rationale: An atom is the fundamental building block of an element, consisting of a nucleus and electrons.

3. Which of the following substances is an example of an acidic gas?

A. Nitrogen (Nâ‚‚)
B. Carbon dioxide (COâ‚‚)
C. Sulfur dioxide (SOâ‚‚)
D. Oxygen (Oâ‚‚)

Correct answer: C

Rationale: Sulfur dioxide is an acidic gas. The other choices are either neutral or basic gases.

4. Which type of waves do not require a medium for propagation?

A. Transverse waves
B. Longitudinal waves
C. Electromagnetic waves
D. Surface waves

Correct answer: c

Rationale: Electromagnetic waves (such as light or radio waves) can travel through a vacuum as they do not require a medium.

5. What is a mutation?

A. A change in the DNA sequence
B. A type of protein
C. A normal part of the DNA replication process
D. A harmless variation in DNA

Correct answer: A

Rationale: Rationale: A mutation is defined as a change in the DNA sequence. Mutations can occur due to various factors such as errors during DNA replication, exposure to mutagens (e.g., chemicals, radiation), or spontaneous changes. These changes can result in alterations to the genetic information carried by an organism, which can have different effects ranging from harmless variations to causing genetic disorders or diseases. Mutations are a fundamental aspect of genetic diversity and evolution. Options B, C, and D do not accurately describe what a mutation is.