1. What is a lifestyle practice that can weaken the immune system?

A. Getting enough sleep
B. Eating a balanced diet rich in fruits and vegetables
C. Managing stress levels
D. Frequent smoking

Correct answer: D

Rationale: Frequent smoking is a lifestyle practice that can weaken the immune system. Smoking has been linked to various health issues, including suppressing the immune system's ability to fight off infections and diseases. The chemicals in tobacco smoke can impair immune function, making smokers more susceptible to illnesses. On the other hand, getting enough sleep, eating a balanced diet rich in fruits and vegetables, and managing stress levels are practices that support a healthy immune system, rather than weaken it.

2. A news article claims a scientist has discovered a single, universal cure for all allergies. This claim seems:

A. Entirely plausible and should be immediately accepted.
B. Unlikely and warrants further investigation and verification.
C. Impossible because allergies have diverse causes.
D. Irrelevant as long as it can help some people alleviate suffering.

Correct answer: B

Rationale: Science rarely offers universal solutions for complex biological phenomena. Extraordinary claims require extraordinary evidence and independent verification.

3. What is the mass number of an element?

A. The number of protons in an atom's nucleus.
B. The number of neutrons in an atom's nucleus.
C. The number of electrons in an atom's valence shell.
D. The number of isotopes of an element.

Correct answer: B

Rationale: The mass number of an element is the total number of protons and neutrons in the nucleus of an atom. It is represented by the symbol A and is written as a superscript to the element's symbol. For example, the mass number of carbon-12 is 12, which means that a carbon-12 atom has 6 protons and 6 neutrons in its nucleus.

4. What is the difference between a sensory neuron and a motor neuron?

A. Sensory neurons carry signals away from the brain, while motor neurons carry signals towards the brain.
B. Sensory neurons control voluntary muscles, while motor neurons control involuntary muscles.
C. Sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system.
D. Sensory neurons detect light, while motor neurons detect sound.

Correct answer: A

Rationale: The correct answer is A because sensory neurons are responsible for carrying signals from sensory receptors towards the central nervous system (brain and spinal cord), allowing us to perceive sensations such as touch, taste, smell, sight, and sound. On the other hand, motor neurons carry signals from the central nervous system to muscles and glands, enabling movement and responses. Therefore, sensory neurons carry signals away from the brain, while motor neurons carry signals towards the brain, making option A the most accurate choice among the options provided.

5. 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.