1. Vacuoles are large sacs for storage in plant cells. What is their main function in animal cells?

A. Protein synthesis
B. Waste storage and disposal
C. Photosynthesis
D. Cellular respiration

Correct answer: B

Rationale: Vacuoles in plant cells are primarily used for storage of water, nutrients, and waste products. In animal cells, vacuoles are smaller and serve various functions, including waste storage and disposal. Option B, 'Waste storage and disposal,' is the correct answer because vacuoles in animal cells help maintain cellular homeostasis by storing and breaking down waste materials. This process aids in detoxification and maintaining proper cellular function in animal cells, similar to the role of vacuoles in plant cells.

2. Which of the following is a MAJOR consequence of a stroke?

A. Irregular heart rhythm.
B. Rapid weight gain or loss.
C. Brain damage due to interrupted blood flow.
D. Chronic fatigue and muscle weakness.

Correct answer: C

Rationale: The correct answer is C: 'Brain damage due to interrupted blood flow.' A stroke occurs when there is a sudden interruption in the blood supply to the brain, leading to brain damage. This interruption can result in various consequences such as paralysis, speech and vision problems, cognitive impairments, and in severe cases, even death. Other options like 'Irregular heart rhythm' (A) and 'Chronic fatigue and muscle weakness' (D) can be associated with health conditions but are not direct consequences of a stroke. 'Rapid weight gain or loss' (B) is typically not a major consequence of a stroke compared to the significant impact of brain damage.

3. What happens to the frequency of a wave if its wavelength decreases while the speed remains constant?

A. Frequency decreases
B. Frequency increases
C. Frequency remains constant
D. Frequency becomes zero

Correct answer: b

Rationale: If the speed of the wave remains constant while the wavelength decreases, the frequency of the wave increases.

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. Dandruff is caused by

A. Excessive sebum production (This can contribute to oily dandruff)
B. Bacterial infection (This can cause scalp folliculitis, not dandruff)
C. Overgrowth of a specific type of fungus on the scalp
D. Lack of proper skin hydration

Correct answer: C

Rationale: Dandruff is primarily caused by an overgrowth of a specific type of fungus called Malassezia on the scalp. This fungus feeds on the natural oils produced by the hair follicles, leading to an inflammatory response in some individuals, resulting in flaking and itching. Excessive sebum production can contribute to oily dandruff by providing more food for the fungus. Bacterial infections, such as scalp folliculitis, can cause symptoms similar to dandruff but are not the primary cause. Lack of proper skin hydration can contribute to dry scalp conditions but is not the main cause of dandruff.

6. Which of the following numbers is a perfect square?

A. 10
B. 12
C. 15
D. 16

Correct answer: D

Rationale: A perfect square is a number obtained by squaring an integer. 16 is the result of squaring 4 (4 x 4 = 16). The other answer choices are not the product of squaring any whole number.