1. What is the main target organ for insulin, the hormone produced by the pancreas?

A. Liver
B. Kidneys
C. Muscles
D. Brain

Correct answer: C

Rationale: The correct answer is C: Muscles. Insulin is a hormone produced by the pancreas that plays a crucial role in regulating blood sugar levels. Its main target organs are the liver, muscles, and adipose tissue. Insulin acts on muscle cells to promote glucose uptake and storage as glycogen, helping to lower blood sugar levels. While the liver and adipose tissue are also important targets for insulin, muscles are particularly significant for glucose utilization and storage. Therefore, muscles are considered the main target organ for insulin in the body.

2. What is the primary hormone released by the parathyroid glands?

A. Insulin
B. Calcitonin
C. Parathyroid hormone (PTH)
D. Thyroxine

Correct answer: C

Rationale: The primary hormone released by the parathyroid glands is Parathyroid hormone (PTH), which plays a crucial role in regulating calcium levels in the body. Insulin is produced by the pancreas to regulate blood sugar levels and is unrelated to the parathyroid glands. Calcitonin is produced by the thyroid gland and helps regulate calcium levels but is not the primary hormone released by the parathyroid glands. Thyroxine is a hormone produced by the thyroid gland that regulates metabolism and is also not released by the parathyroid glands. Therefore, the correct answer is C: Parathyroid hormone (PTH).

3. Which element is used in fertilizers due to its role in plant cell division and growth?

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

Correct answer: B

Rationale: Phosphorus is crucial for cell division and metabolism, making it essential for plant growth and development.

4. What is the main purpose of biological classification?

A. To create a rigid and unchanging system for labeling organisms
B. To understand the diversity and interconnectedness of life
C. To simplify nature into neat and tidy categories
D. To assign organisms to specific ecological niches

Correct answer: B

Rationale: Rationale: Biological classification, also known as taxonomy, is the science of categorizing and organizing living organisms based on shared characteristics. The main purpose of biological classification is not to create a rigid and unchanging system (option A) or to simplify nature into neat and tidy categories (option C). Instead, it aims to help us understand the diversity of life on Earth and how different organisms are related to each other. By classifying organisms into groups based on their evolutionary relationships, we can gain insights into the interconnectedness of life and better appreciate the complexity and beauty of the natural world. Assigning organisms to specific ecological niches (option D) is more related to ecological studies rather than biological classification.

5. Which blood type is a universal donor?

A. A
B. B
C. AB
D. O

Correct answer: D

Rationale: Rationale: Blood type O is considered the universal donor because individuals with type O blood can donate red blood cells to individuals with any ABO blood type (A, B, AB, or O) without causing an adverse reaction. This is because type O blood lacks A or B antigens on the surface of red blood cells, which helps minimize the risk of an immune response when transfused into individuals with different blood types. Therefore, type O blood is in high demand for blood transfusions in emergency situations when the recipient's blood type is unknown or when there is a shortage of specific blood types.