1. Scoliosis is a condition characterized by abnormal lateral curvature of the spine. Which part of the spine is most commonly affected?

A. Cervical spine (neck)
B. Thoracic spine (upper back)
C. Lumbar spine (lower back)
D. All of the above

Correct answer: B

Rationale: The correct answer is B: Thoracic spine (upper back). Scoliosis typically affects the thoracic spine more commonly than the cervical or lumbar spine. The thoracic spine, which is the upper back region, is the most common area for the abnormal lateral curvature of the spine to occur in cases of scoliosis. This is due to the natural curvature and structure of the spine in this region. While scoliosis can affect other parts of the spine as well, the thoracic spine is most frequently impacted, making it the correct answer in this case.

2. 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

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. What disease is characterized by progressive muscle weakness and wasting?

A. Muscular dystrophy
B. Myositis
C. Fibromyalgia
D. Carpal tunnel syndrome

Correct answer: A

Rationale: The correct answer is A: Muscular dystrophy. Muscular dystrophy is a genetic disorder characterized by progressive muscle weakness and wasting over time. It primarily affects skeletal muscles, leading to difficulties in movement and muscle function. Myositis is an inflammatory condition affecting the muscles, but it may not always result in progressive muscle weakness and wasting. Fibromyalgia is a chronic pain disorder characterized by widespread musculoskeletal pain and fatigue, not necessarily progressive muscle weakness. Carpal tunnel syndrome is a compression neuropathy affecting the median nerve in the wrist, leading to symptoms like numbness and tingling in the hand, but it does not cause progressive muscle weakness and wasting like muscular dystrophy does.

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.

6. What is the name of the regulatory region in a gene that controls its expression?

A. Exon
B. Intron
C. Promoter
D. Enhancer

Correct answer: C

Rationale: Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression. B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression. C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression. D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter. Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.