1. Kidney stones are formed when:

A. Excess water is not reabsorbed
B. Minerals crystallize in the urine
C. Electrolytes become too concentrated
D. All of the above

Correct answer: B

Rationale: The correct answer is B: "Minerals crystallize in the urine." Kidney stones are formed when minerals in the urine combine and crystallize, forming solid masses. This process can occur due to various factors, such as high levels of calcium, oxalate, or uric acid in the urine. Options A and C are not directly related to the formation of kidney stones. Option D is incorrect because not all the statements are true; only minerals crystallizing in the urine lead to kidney stone formation.

2. What is the main function of vacuoles in plant cells?

A. To provide structural support for the cell
B. To transport substances in and out of the cell
C. To synthesize proteins and lipids
D. To store water, enzymes, and waste products

Correct answer: D

Rationale: Rationale: Vacuoles in plant cells primarily function as storage organelles. They store water, enzymes, pigments, and waste products. Vacuoles help maintain turgor pressure within the cell, which provides structural support for the plant cell. While vacuoles can also be involved in transporting substances within the cell, their main function is storage. Synthesizing proteins and lipids is primarily carried out by other organelles such as the endoplasmic reticulum and Golgi apparatus.

3. What property of a substance refers to its ability to be drawn into thin wires without breaking?

A. Malleability
B. Viscosity
C. Ductility
D. Conductivity

Correct answer: c

Rationale: Ductility is the property that describes a substance's ability to be drawn into thin wires without breaking.

4. The largest bone in the human body is the:

A. Femur (thigh bone)
B. Tibia (shin bone)
C. Humerus (upper arm bone)
D. Scapula (shoulder blade)

Correct answer: A

Rationale: The correct answer is A: Femur (thigh bone). The femur is the longest and strongest bone in the human body, located in the thigh region. It plays a crucial role in supporting the body's weight and facilitating movement. The tibia (B) is commonly known as the shin bone and is located below the femur. The humerus (C) is the upper arm bone, and the scapula (D) is the shoulder blade. However, neither of these bones is the largest in the human body. Understanding the anatomy of the skeletal system is essential for identifying the largest bone in the body, which is the femur.

5. Antibodies, crucial for immune defense, are produced by:

A. Neutrophils
B. Lymphocytes
C. Monocytes
D. Basophils

Correct answer: B

Rationale: The correct answer is B: Lymphocytes. Antibodies, also known as immunoglobulins, are produced by B lymphocytes (B cells) as a key component of the adaptive immune response. These specialized cells play a crucial role in recognizing and neutralizing pathogens, thereby providing immunity against infections. Neutrophils (A) are a type of white blood cell involved in innate immunity and phagocytosis. Monocytes (C) are another type of white blood cell that can differentiate into macrophages, which are important in phagocytosis and antigen presentation. Basophils (D) are involved in allergic responses and inflammation through the release of histamine. Lymphocytes, particularly B cells, are primarily responsible for antibody production in response to pathogens and foreign substances.

6. Which of the following is a property of amphiprotic substances?

A. React with acids only
B. React with bases only
C. Can act as both acids and bases
D. Are inert in chemical reactions

Correct answer: C

Rationale: Amphiprotic substances can donate or accept a proton, so they can act as both acids and bases. The other choices do not accurately describe amphiprotic substances.