1. The muscular sac that stores urine until it is released from the body is called the:

A. Urethra
B. Bladder
C. Ureter
D. Nephron

Correct answer: B

Rationale: The correct answer is B: Bladder. The bladder is a muscular sac that stores urine until it is ready to be released from the body through the urethra. The urethra is the tube that carries urine from the bladder out of the body. Ureters are tubes that carry urine from the kidneys to the bladder. Nephrons are the functional units of the kidneys responsible for filtering the blood and producing urine. Therefore, the bladder is the specific organ responsible for storing urine until it is expelled from the body, making it the correct answer.

2. Which of the following is a characteristic of unsaturated fatty acids?

A. They are solid at room temperature.
B. They contain only single bonds.
C. They have a higher melting point.
D. They contain double or triple bonds.

Correct answer: D

Rationale: Unsaturated fatty acids contain double or triple bonds in their hydrocarbon chains. The other choices do not accurately describe unsaturated fatty acids.

3. A salt solution that conducts electricity well is most likely

A. A saturated solution
B. A concentrated solution of a strong electrolyte
C. A dilute solution of a weak acid
D. A mixture of a neutral compound and water

Correct answer: B

Rationale: The correct answer is B: "A concentrated solution of a strong electrolyte." Strong electrolytes completely dissociate into ions in solution, thereby increasing the conductivity of the solution. Concentrated solutions have a higher amount of dissolved solute particles, which leads to more ions available for conducting electricity. In contrast, saturated solutions may contain undissolved solute, limiting the number of ions in solution. Dilute solutions have fewer ions and weak acids only partially dissociate, reducing conductivity. A neutral compound and water do not provide ions for conducting electricity. Therefore, a concentrated solution of a strong electrolyte is most likely to conduct electricity well due to the high concentration of ions present.

4. What is the main component of sweat?

A. Urea
B. Glucose
C. Water
D. Electrolytes

Correct answer: C

Rationale: Rationale: - Sweat is primarily composed of water, making up the majority of its content. Water helps regulate body temperature by evaporating from the skin's surface, which cools the body down. - While sweat does contain small amounts of other substances like urea, glucose, and electrolytes, water is the main component that is secreted by sweat glands to help regulate body temperature during physical activity or in response to heat.

5. What term describes the bouncing back of waves after striking a surface or boundary?

A. Diffraction
B. Refraction
C. Reflection
D. Interference

Correct answer: c

Rationale: Reflection occurs when waves bounce back after hitting a surface or boundary.

6. What is the protective fluid that surrounds the brain and spinal cord?

A. Blood
B. Cerebrospinal fluid
C. Myelin sheath
D. Insulin

Correct answer: B

Rationale: The correct answer is B: Cerebrospinal fluid. This fluid acts as a cushion for the brain and spinal cord, providing protection from impacts. Blood is essential for transporting nutrients and oxygen, but it does not directly surround or protect these vital nervous system structures. Myelin sheath is a fatty substance that insulates nerve fibers, not the fluid surrounding the nervous system. Insulin is a hormone involved in regulating blood sugar levels and is not related to protecting the brain and spinal cord.