1. The basic unit of communication in the nervous system is called a:

A. Neuron
B. Astrocyte
C. Neurotransmitter
D. Synapse

Correct answer: A

Rationale: The basic unit of communication in the nervous system is a neuron. Neurons are specialized cells that transmit information through electrical and chemical signals. They form complex networks to relay messages throughout the body. Astrocytes are support cells that help maintain the environment around neurons. Neurotransmitters are chemicals that transmit signals between neurons at synapses. A synapse is a junction between two neurons where communication occurs. However, the primary unit responsible for communication in the nervous system is the neuron, making it the correct answer.

2. Why are isotopes of the same element chemically similar?

A. They have the same number of protons.
B. They have the same number of electrons.
C. Their chemical properties are identical.
D. They share the same electron configuration.

Correct answer: A

Rationale: They have the same number of protons. This determines the element's identity and its interactions with other elements, leading to similar chemical behavior, even if the number of neutrons differs.

3. Identify the bone with the greatest length in the human body.

A. Femur (Thigh bone)
B. Humerus (Upper arm bone)
C. Tibia (Shin bone)
D. Scapula (Shoulder blade)

Correct answer: A

Rationale: The femur, exceeding a meter in length, bears significant weight and enables locomotion.

4. What is the primary function of the coronary arteries in the cardiovascular system?

A. Carry oxygenated blood to the heart muscle
B. Carry deoxygenated blood from the heart muscle
C. Pump blood to the lungs for oxygenation
D. Regulate blood pressure in the systemic circulation

Correct answer: A

Rationale: The primary function of the coronary arteries in the cardiovascular system is to carry oxygenated blood to the heart muscle. These arteries supply the heart muscle with the necessary oxygen and nutrients it needs to function properly. Without adequate blood flow through the coronary arteries, the heart muscle can become deprived of oxygen, leading to conditions like angina or even a heart attack. Options B, C, and D are incorrect as they do not accurately describe the function of the coronary arteries. Option B is incorrect because the coronary arteries carry oxygenated blood, not deoxygenated blood. Option C is incorrect because the pulmonary arteries, not the coronary arteries, carry blood to the lungs for oxygenation. Option D is incorrect because the regulation of blood pressure in the systemic circulation is primarily controlled by mechanisms such as the kidneys and the autonomic nervous system, not the coronary arteries.

5. A new material is claimed to be stronger than steel. You design an experiment to test this claim. What is the MOST important control variable?

A. The size of the material samples.
B. The temperature at which the test is conducted.
C. The force applied to the material.
D. The color of the material.

Correct answer: A

Rationale: The size of the material samples is the most important control variable because it ensures that the comparison between the new material and steel is fair and accurate. By keeping the size consistent, any differences in strength can be attributed to the material composition rather than variations in sample size. Controlling for size helps eliminate confounding variables and increases the reliability of the experiment results. Temperature, force applied, and color are not as critical for directly testing the strength comparison between the new material and steel.

6. Neurons, the functional units of the nervous system, belong to which tissue type?

A. Epithelial tissue
B. Connective tissue
C. Muscle tissue
D. Nervous tissue

Correct answer: D

Rationale: The correct answer is D: Nervous tissue. Neurons are specialized cells that transmit nerve impulses and are the primary components of the nervous system. Nervous tissue is made up of neurons and supporting cells called neuroglia. Neurons are responsible for processing and transmitting information throughout the body, making them a crucial part of the nervous system. Epithelial tissue (A) is primarily involved in covering and lining surfaces, connective tissue (B) supports and connects other tissues, and muscle tissue (C) is responsible for movement. Therefore, neurons belong to nervous tissue, which is specialized for communication and coordination within the body.