1. Which mineral is crucial for bone strength and is stored in bones and teeth?

A. Calcium
B. Iron
C. Magnesium
D. Potassium

Correct answer: A

Rationale: The correct answer is A: Calcium. Calcium is crucial for bone strength as it is a key mineral stored in bones and teeth. It plays a vital role in maintaining bone density and strength, helping to prevent conditions like osteoporosis. Without an adequate intake of calcium, individuals may be at risk of developing weak and brittle bones. Iron (B), Magnesium (C), and Potassium (D) are important minerals for various bodily functions, but they are not primarily responsible for bone strength and storage in bones and teeth.

2. A closed system in ecology is one that:

A. Exchanges energy but not matter
B. Exchanges both energy and matter
C. Exchanges neither energy nor matter
D. Recycles nutrients efficiently

Correct answer: A

Rationale: Rationale: In ecology, a closed system is one that does not exchange matter with its surroundings but can exchange energy. This means that while energy can enter or leave the system, the amount of matter within the system remains constant. This definition aligns with option A, making it the correct answer. Options B and C are incorrect because a closed system does not exchange matter, and option D is not directly related to the definition of a closed system in ecology.

3. Identify the comprehensive protection for the brain.

A. Skull
B. Meninges (Membranes)
C. Cerebrospinal fluid
D. All of the above

Correct answer: D

Rationale: Rationale: A) The skull provides a hard, protective covering for the brain, shielding it from external trauma and injury. B) The meninges are three layers of membranes (dura mater, arachnoid mater, and pia mater) that surround the brain and spinal cord, providing additional protection and cushioning. C) Cerebrospinal fluid is a clear, colorless fluid that surrounds the brain and spinal cord, acting as a shock absorber and providing nutrients to the central nervous system. Together, the skull, meninges, and cerebrospinal fluid work in conjunction to provide comprehensive protection for the brain, making option D the correct answer.

4. A ball is thrown upwards. Which of the following statements is TRUE about its potential energy and kinetic energy at the peak of its trajectory?

A. Both potential and kinetic energy are zero.
B. Potential energy is maximum and kinetic energy is minimum.
C. Potential energy is minimum and kinetic energy is maximum.
D. Both potential and kinetic energy remain constant.

Correct answer: B

Rationale: At the peak, the ball momentarily stops moving, minimizing kinetic energy. However, it's still at its highest point, maximizing its potential energy due to gravity.

5. What is an example of a fibrous protein?

A. Insulin
B. Keratin
C. Hemoglobin
D. Collagen

Correct answer: D

Rationale: Rationale: A) Insulin is a hormone, not a fibrous protein. Insulin is produced in the pancreas and is involved in regulating blood sugar levels. B) Keratin is a fibrous structural protein found in hair, nails, and the outer layer of skin. It provides strength and protection. C) Hemoglobin is a globular protein found in red blood cells that is responsible for carrying oxygen from the lungs to the rest of the body. It is not a fibrous protein. D) Collagen is a fibrous protein that is the main component of connective tissues such as tendons, ligaments, and skin. It provides strength and structure to these tissues.

6. The muscular tube that connects the mouth to the stomach is called the:

A. Pharynx
B. Esophagus
C. Trachea
D. Larynx

Correct answer: B

Rationale: The correct answer is B: Esophagus. The esophagus is the muscular tube that connects the mouth to the stomach. It plays a crucial role in transporting food from the mouth to the stomach through peristaltic movements. The pharynx is the part of the throat that connects the mouth and nasal cavity to the esophagus and trachea. The trachea, also known as the windpipe, is responsible for carrying air to and from the lungs. The larynx, commonly known as the voice box, is involved in producing sound and protecting the trachea during swallowing. Therefore, the esophagus is specifically responsible for food transport from the mouth to the stomach.