1. Cartilage is a flexible connective tissue found in the:

A. Center of long bones
B. Joints between bones
C. Muscle tissue
D. Walls of blood vessels

Correct answer: A

Rationale: Cartilage is a flexible connective tissue that is found in the joints between bones. It is a strong yet flexible tissue that cushions and supports the joints, allowing for smooth movement and reducing friction between bones. Cartilage is not typically found in the center of long bones, muscle tissue, or walls of blood vessels. Therefore, the correct answer is B: 'Joints between bones.'

2. When an atom gains or loses electrons, it becomes a(n):

A. Molecule
B. Isotope
C. Ion
D. Compound

Correct answer: C

Rationale: Gaining or losing electrons alters the atom's electron count and charge, creating a positively or negatively charged ion.

3. Action potentials, the all-or-nothing electrical signals traveling along neurons, are generated by the movement of:

A. Glucose
B. Sodium and potassium ions
C. Neurotransmitters
D. Myelin

Correct answer: B

Rationale: The correct answer is B: Sodium and potassium ions. Action potentials are generated by the movement of sodium and potassium ions across the neuronal membrane. During depolarization, sodium ions rush into the cell, causing a change in electrical charge. This influx of positive ions triggers the opening of voltage-gated potassium channels, allowing potassium ions to exit the cell during repolarization. Glucose is a source of energy for cells but does not directly generate action potentials. Neurotransmitters are chemical messengers released at synapses, while myelin is a fatty substance that insulates axons, speeding up the conduction of action potentials but not directly generating them.

4. Which of the following is the main organ responsible for filtering urine?

A. Kidneys
B. Bladder
C. Ureters
D. Urethra

Correct answer: A

Rationale: Rationale: The kidneys are the main organs responsible for filtering urine. They play a crucial role in the urinary system by filtering waste products and excess substances from the blood to produce urine. The urine then travels from the kidneys to the bladder through the ureters, where it is stored until it is expelled from the body through the urethra. The bladder stores urine temporarily, while the ureters are tubes that transport urine from the kidneys to the bladder. The urethra is the tube through which urine is expelled from the body.

5. Which of the following is NOT a recognized mode of natural selection?

A. Directional selection (favoring one extreme trait value on a spectrum)
B. Disruptive selection (favoring both extreme trait values on a spectrum)
C. Stabilizing selection (favoring the average trait value on a spectrum)
D. Sexual selection (selection based on mate choice that influences reproductive success)

Correct answer: D

Rationale: Rationale: A) Directional selection is a recognized mode of natural selection where one extreme trait value on a spectrum is favored over others. This can lead to a shift in the average trait value over time. B) Disruptive selection is a recognized mode of natural selection where both extreme trait values on a spectrum are favored over the average trait value. This can lead to the population splitting into two distinct groups. C) Stabilizing selection is a recognized mode of natural selection where the average trait value on a spectrum is favored over extreme values. This can lead to a reduction in genetic diversity within a population. D) Sexual selection is not a mode of natural selection in the traditional sense, as it involves mate choice and competition for mates rather than direct selection pressure on traits that affect survival and reproduction in the environment. Sexual selection can lead to the evolution of traits that enhance an individual's ability to attract

6. What happens to the frequency of a wave when its wavelength is doubled, assuming the speed remains constant?

A. Frequency remains the same.
B. Frequency is halved.
C. Frequency is doubled.
D. Frequency information is insufficient to determine.

Correct answer: C

Rationale: Since the wave speed is constant, if the wavelength increases, the frequency must decrease to maintain the same energy transfer per unit time.