1. Which hormone, produced by the pancreas, acts in opposition to insulin by increasing blood sugar levels?

A. Insulin
B. Glucagon
C. Cortisol
D. Thyroxine

Correct answer: b

Rationale: The correct answer is B: Glucagon. Glucagon is a hormone produced by the pancreas that acts in opposition to insulin. When blood sugar levels are low, glucagon stimulates the liver to convert stored glycogen into glucose, which raises blood sugar levels. Insulin, on the other hand, lowers blood sugar levels by promoting the uptake and storage of glucose. Cortisol, produced by the adrenal glands, plays a role in stress response and metabolism but does not directly regulate blood sugar levels. Thyroxine, produced by the thyroid gland, regulates metabolism but does not directly affect blood sugar levels. Therefore, glucagon is the hormone that acts in opposition to insulin by increasing blood sugar levels.

2. Organisms that break down dead organisms and return nutrients to the environment are called:

A. Producers
B. Decomposers
C. Consumers
D. Parasites

Correct answer: B

Rationale: Rationale: Decomposers are organisms that break down dead organisms and organic matter, such as bacteria, fungi, and some insects. They play a crucial role in the ecosystem by breaking down complex organic materials into simpler forms, releasing nutrients back into the environment for other organisms to use. Producers (option A) are organisms that produce their own food through photosynthesis, consumers (option C) are organisms that consume other organisms for energy, and parasites (option D) are organisms that live on or in another organism and benefit at the host's expense.

3. What is the 3D structure of a protein called?

A. Tertiary structure
B. Secondary structure
C. Primary structure
D. Quaternary structure

Correct answer: A

Rationale: Rationale: - Primary structure refers to the linear sequence of amino acids in a protein. - Secondary structure refers to local folded structures within a protein, such as alpha helices and beta sheets. - Tertiary structure is the overall 3D shape of a protein, which is determined by interactions between amino acid side chains and the environment. - Quaternary structure refers to the arrangement of multiple protein subunits in a protein complex. Therefore, the 3D structure of a protein is called the tertiary structure because it represents the overall folding of the protein into a specific shape.

4. Which of the following is NOT a function of the skeletal system?

A. Support and structure
B. Production of red blood cells
C. Storage of minerals like calcium
D. Insulation of the body

Correct answer: A

Rationale: The correct answer is A. The skeletal system provides support and structure to the body, allowing for movement and protecting internal organs. The production of red blood cells occurs in the bone marrow, which is a function of the skeletal system. Additionally, the skeletal system stores minerals like calcium, which play a crucial role in bone health and overall bodily functions. Insulation of the body is not a primary function of the skeletal system but is rather a function of adipose tissue and the integumentary system. Therefore, option A is the correct answer as it does not align with the functions of the skeletal system.

5. Nervous tissue is responsible for

A. Movement
B. Protection
C. Communication and coordination
D. Nutrient transport

Correct answer: C

Rationale: Nervous tissue is responsible for communication and coordination within the body. This tissue includes neurons and supporting cells, which work together to transmit electrical signals and information throughout the body. Movement is primarily controlled by the muscular system, protection is the role of the immune system and skin, while nutrient transport is primarily handled by the circulatory system. Therefore, the correct answer is C: 'Communication and coordination.'

6. Coronary arteries are responsible for:

A. Delivering oxygenated blood throughout the body.
B. Supplying oxygenated blood to the heart muscle itself.
C. Carrying deoxygenated blood back to the heart.
D. Regulating blood pressure through vasoconstriction and vasodilation.

Correct answer: B

Rationale: The correct answer is B: 'Supplying oxygenated blood to the heart muscle itself.' Coronary arteries are specialized blood vessels that branch off the aorta and provide oxygenated blood to the heart muscle. This is crucial for the heart to function properly and maintain its own blood supply separate from the systemic circulation. The other options are incorrect because delivering oxygenated blood throughout the body is the role of the systemic circulation and not specific to coronary arteries. Carrying deoxygenated blood back to the heart is the function of veins, while regulating blood pressure through vasoconstriction and vasodilation is primarily controlled by arteries in general, not just the coronary arteries.