1. Calcitonin, a hormone that helps regulate calcium levels, is produced by the:

A. Thyroid gland
B. Parathyroid gland
C. Thymus gland
D. Adrenal gland

Correct answer: A

Rationale: The correct answer is A: "Thyroid gland." Calcitonin is a hormone produced by the thyroid gland that helps regulate calcium levels in the body. It works in opposition to parathyroid hormone, which is produced by the parathyroid gland. The thymus gland is responsible for immune function, while the adrenal gland produces hormones like cortisol and adrenaline. Therefore, the thyroid gland is the specific gland responsible for producing calcitonin to regulate calcium levels in the body.

2. Which of the following is the main organ responsible for storing energy?

A. Liver
B. Heart
C. Kidneys
D. Adipose tissue

Correct answer: D

Rationale: Rationale: - Adipose tissue, commonly known as body fat, is the main organ responsible for storing energy in the form of triglycerides. - The liver plays a role in energy metabolism by regulating glucose levels and storing glycogen, but its primary function is not energy storage. - The heart is a muscular organ responsible for pumping blood throughout the body and does not play a significant role in energy storage. - The kidneys are vital organs responsible for filtering blood and regulating fluid balance, but they are not primarily involved in energy storage.

3. The longest bone in the human body is the:

A. Tibia
B. Fibula
C. Femur
D. Humerus

Correct answer: C

Rationale: The correct answer is C: "Femur." The femur is the longest bone in the human body, located in the thigh region and connecting the hip to the knee. It plays a crucial role in supporting the body's weight and facilitating movement. The tibia and fibula are bones in the lower leg, while the humerus is a bone in the upper arm. Therefore, the femur is the correct answer for the longest bone in the human body.

4. The fluid-filled, jelly-like substance within the cell that suspends the organelles is called the:

A. Nucleus
B. Cytoplasm
C. Plasma membrane
D. Golgi apparatus

Correct answer: B

Rationale: The correct answer is B: Cytoplasm. Cytoplasm is the fluid-filled, jelly-like substance within the cell that suspends the organelles. It is where many cellular processes take place, such as metabolism and protein synthesis. The nucleus (option A) is the organelle that contains the cell's genetic material, the plasma membrane (option C) is the outer boundary of the cell that regulates what enters and exits the cell, and the Golgi apparatus (option D) is involved in processing and packaging proteins. Understanding the functions of each organelle is crucial in recognizing that the cytoplasm is the correct answer in this context.

5. What is the main point of the passage?

A. Climate change is a myth and does not pose any significant threat to the planet.
B. The negative consequences of climate change are inevitable and irreversible.
C. Human actions are the primary cause of climate change, and global efforts are needed to address it.
D. Technological advancements alone can provide quick and easy solutions to the climate crisis.

Correct answer: C

Rationale: The passage clearly identifies human activities as the cause of climate change and emphasizes the need for global action, aligning with C.

6. What is the breakdown product of creatine phosphate, an energy source used for short bursts of muscle activity?

A. Glucose
B. Lactic acid
C. Carbon dioxide
D. Creatine

Correct answer: D

Rationale: The breakdown product of creatine phosphate is creatine. Creatine phosphate is stored in muscle cells and rapidly converts to creatine to provide energy for short bursts of muscle activity, such as weightlifting or sprinting. It is not converted into glucose, lactic acid, or carbon dioxide. Creatine is then further broken down into creatinine, which is excreted in urine. Therefore, the correct answer is D: Creatine.