1. During vigorous exercise, the respiratory rate increases to:

A. Meet the increased demand for oxygen in working muscles
B. Eliminate excess carbon dioxide more slowly
C. Conserve energy for physical activity
D. Decrease the amount of oxygen delivered to the body

Correct answer: A

Rationale: During vigorous exercise, the respiratory rate increases to meet the increased demand for oxygen in working muscles. When we exercise vigorously, our muscles require more oxygen to produce energy through aerobic metabolism. Increasing the respiratory rate allows more oxygen to be taken in and transported to the muscles via the bloodstream to support this increased demand. Option A is correct because it accurately reflects the physiological response of the respiratory system to vigorous exercise, ensuring that working muscles receive sufficient oxygen for optimal performance.

2. A lampshade consists of a cylindrical base (diameter 20cm, height 10cm) and a hemispherical top (same diameter as the base). What is its total surface area?

A. 785 sq cm
B. 1130 sq cm
C. 1570 sq cm
D. 2055 sq cm

Correct answer: D

Rationale: Calculate the surface area of the cylinder (base + lateral surface) and the hemisphere (half of a sphere's surface area). Add both areas to find the total surface area.

3. In which direction do the particles of the medium move in a transverse wave?

A. Perpendicular to the direction of wave travel
B. Parallel to the direction of wave travel
C. In a circular motion
D. Opposite to the direction of wave travel

Correct answer: a

Rationale: In a transverse wave, particle displacement occurs perpendicular to the direction of wave travel.

4. Which organelle is responsible for carrying out photosynthesis in plant cells?

A. Golgi apparatus
B. Mitochondria
C. Chloroplasts
D. Lysosomes

Correct answer: C

Rationale: Rationale: A) Golgi apparatus: The Golgi apparatus is responsible for modifying, sorting, and packaging proteins for secretion or for use within the cell. It is not involved in photosynthesis. B) Mitochondria: Mitochondria are known as the powerhouse of the cell and are responsible for generating energy in the form of ATP through cellular respiration. They are not involved in photosynthesis. C) Chloroplasts: Chloroplasts are the organelles responsible for carrying out photosynthesis in plant cells. They contain chlorophyll, a pigment that captures light energy and converts it into chemical energy in the form of glucose. D) Lysosomes: Lysosomes are membrane-bound organelles that contain digestive enzymes to break down waste materials and cellular debris. They are not involved in photosynthesis. Therefore, the correct answer is C) Chloroplasts, as they are specifically responsible for carrying out photosynthesis in plant

5. In a horizontal chart, the lowest level worker is located at the

A. Leftmost box
B. Middle
C. Rightmost box
D. Bottom

Correct answer: B

Rationale: In a horizontal chart, the lowest level worker is typically positioned at the leftmost side, with higher-level workers placed to the right. This arrangement signifies hierarchy, with the top level usually being on the rightmost side. Therefore, the correct answer is B: 'Middle,' as the lowest level worker is situated towards the left of the chart, not the extreme left or right. This positioning helps visually represent the organization's structure and indicates the progression from lower to higher levels as one moves from left to right on the chart.

6. Melanin, the pigment responsible for skin color, is produced by

A. Keratinocytes (These cells produce keratin)
B. Melanocytes
C. Sebocytes (These cells produce sebum)
D. Langerhans cells (These cells are part of the immune system)

Correct answer: B

Rationale: The correct answer is B: Melanocytes. Melanin, the pigment responsible for skin color, is produced by melanocytes, which are specialized cells located in the skin's epidermis. Melanocytes transfer melanin to keratinocytes, the predominant cell type in the epidermis, where it provides protection against UV radiation. Sebocytes produce sebum, an oily substance that helps moisturize the skin and hair. Langerhans cells are a type of immune cell that play a role in the skin's immune response. Therefore, the correct answer is B as melanocytes are specifically responsible for producing melanin.