1. Which vitamin is synthesized in the skin upon exposure to sunlight?

A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin E

Correct answer: A

Rationale: The correct answer is Vitamin D (C). When the skin is exposed to sunlight, a compound in the skin is converted to Vitamin D. Vitamin A (A) is not synthesized in the skin but is found in foods like carrots and sweet potatoes. Vitamin C (B) is not synthesized in the skin either, but is found in citrus fruits and vegetables. Vitamin E (D) is not synthesized in the skin upon sunlight exposure, but is found in nuts and seeds.

2. The phrase "disruptions to ecosystems" refers to

A. Minor inconveniences experienced by plant and animal species due to changing weather patterns.
B. Significant changes in ecological relationships and imbalances in populations and food webs.
C. The aesthetic alteration of landscapes due to melting glaciers and deforestation.
D. The economic losses suffered by industries relying on natural resources affected by climate change.

Correct answer: B

Rationale: The phrase suggests profound impacts on ecological balance and species interactions, aligning with B.

3. Which number is the opposite of -3?

A. -6
B. 3
C. 0
D. 6

Correct answer: B

Rationale: The opposite of a number is the one with the same distance from zero but on the opposite side of the number line. So, the opposite of -3 is 3.

4. What is the recommended daily intake of protein for adults to maintain healthy muscle mass?

A. 0.5 grams per kilogram of body weight
B. 1 gram per kilogram of body weight
C. 1.5 grams per kilogram of body weight
D. 2 grams per kilogram of body weight

Correct answer: C

Rationale: The recommended daily intake of protein for adults to maintain healthy muscle mass is 1.5 grams per kilogram of body weight. Protein is essential for muscle repair and growth, and consuming an adequate amount helps support overall muscle health. 1 gram per kilogram of body weight is generally recommended for sedentary individuals, but for those looking to maintain or build muscle mass, a higher intake of 1.5 grams per kilogram of body weight is advised. Consuming too little protein can lead to muscle loss, while consuming too much may strain the kidneys. Therefore, 1.5 grams per kilogram of body weight strikes a balance for most adults looking to support their muscle health.

5. Which part of the neuron insulates and speeds up the transmission of nerve impulses along the axon?

A. Dendrite
B. Myelin sheath
C. Synapse
D. Cell body

Correct answer: b

Rationale: The correct answer is B: Myelin sheath. The myelin sheath is a fatty substance that surrounds the axon of a neuron, acting as an insulator to speed up the transmission of nerve impulses. It does this by creating gaps called nodes of Ranvier where the nerve impulses jump from one node to the next, allowing for faster signal conduction. Dendrites are branch-like extensions that receive signals from other neurons, the synapse is the junction between two neurons where neurotransmitters are released, and the cell body contains the nucleus and organelles of the neuron, but it is the myelin sheath that specifically insulates and speeds up the transmission of nerve impulses along the axon.

6. How many amino acids can make up a protein?

A. 10-20
B. 50-100
C. 100-500
D. 1000+

Correct answer: A

Rationale: Rationale: Proteins are made up of long chains of amino acids. There are 20 standard amino acids that are commonly found in proteins. The sequence and arrangement of these amino acids determine the structure and function of a protein. While proteins can vary in size and complexity, the number of amino acids typically ranges from around 10 to 20 in smaller proteins to hundreds or even thousands in larger proteins. Therefore, the range of 10-20 amino acids is the most accurate representation of the number of amino acids that can make up a protein.