1. What is the purpose of the periosteum, the tough outer layer of bone?

A. Produces red blood cells
B. Provides protection and nourishment to bone
C. Forms the joint surface
D. Stores minerals

Correct answer: B

Rationale: The correct answer is B: 'Provides protection and nourishment to bone.' The periosteum is a tough outer layer of bone that serves multiple functions. It provides protection by acting as a barrier against infections and injuries. Additionally, the periosteum contains blood vessels that supply nutrients to the bone cells, aiding in bone growth, repair, and maintenance. While red blood cells are produced in the bone marrow, not in the periosteum, the periosteum's primary role is to support the overall health and integrity of the bone structure.

2. A ball is thrown upwards. At the peak of its trajectory, which of the following forces is acting on the ball?

A. Gravity only
B. Gravity and air resistance only
C. Neither gravity nor air resistance
D. All of the above

Correct answer: C

Rationale: At the peak of its trajectory, the ball has momentarily stopped moving upwards and has not yet started to fall back down. Therefore, there is no longer a net force acting on the ball at that instant. Gravity is acting downwards, but since the ball is not moving, the force of gravity is balanced by an equal and opposite force, resulting in a net force of zero. Similarly, air resistance only affects the ball when it is in motion, so at the peak where the ball momentarily stops, there is no air resistance force. Therefore, at the peak of its trajectory, neither gravity nor air resistance is acting on the ball, making option C the correct answer.

3. What is the process by which decomposers break down organic matter?

A. Photosynthesis
B. Bioremediation
C. Decomposition
D. Nitrification

Correct answer: C

Rationale: Rationale: A) Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy to produce glucose from carbon dioxide and water. This process is not related to the breakdown of organic matter by decomposers. B) Bioremediation is the use of living organisms to clean up contaminated environments. While it involves the use of microorganisms to break down pollutants, it is not specifically focused on breaking down organic matter. C) Decomposition is the process by which decomposers such as bacteria, fungi, and other organisms break down organic matter into simpler substances. This process is essential for nutrient recycling in ecosystems. D) Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of nitrite to nitrate by nitrifying bacteria. This process is part of the nitrogen cycle and is not directly related to the breakdown of organic matter.

4. Which of the following describes a vector quantity?

A. Speed
B. Distance
C. Mass
D. Velocity

Correct answer: d

Rationale: Velocity is a vector quantity as it includes both magnitude (speed) and direction.

5. Which of the following is NOT a greenhouse gas?

A. Carbon Dioxide
B. Methane
C. Oxygen
D. Water Vapor

Correct answer: C

Rationale: Rationale: A) Carbon Dioxide: Carbon dioxide is a greenhouse gas that is released into the atmosphere through various human activities such as burning fossil fuels and deforestation. B) Methane: Methane is another greenhouse gas that is released from sources like livestock, landfills, and natural gas production. C) Oxygen: Oxygen is not considered a greenhouse gas. It is a vital component of the Earth's atmosphere that is necessary for respiration and combustion. D) Water Vapor: Water vapor is also a greenhouse gas that plays a significant role in the Earth's climate system by trapping heat in the atmosphere. Therefore, the correct answer is C) Oxygen, as it is not a greenhouse gas.