1. Which part of the neuron receives incoming signals from other neurons and conducts them toward the cell body?

A. Axon
B. Dendrite
C. Synapse
D. Myelin sheath

Correct answer: b

Rationale: The correct answer is B: Dendrite. Dendrites are the part of the neuron that receive incoming signals from other neurons and conduct them toward the cell body. They play a crucial role in communication between neurons by receiving neurotransmitters released from neighboring neurons. Axons transmit signals away from the cell body, synapses are the junctions where neurons communicate with each other, and myelin sheath is a fatty insulation that surrounds and protects axons. Therefore, in this scenario, dendrites are specifically responsible for receiving and conducting incoming signals towards the cell body.

2. Which of the following organs is NOT directly involved in urine production?

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

Correct answer: C

Rationale: The correct answer is C: Lungs. The lungs are not directly involved in urine production. The kidneys are responsible for filtering waste products from the blood to create urine. The urethra is the tube that carries urine from the bladder out of the body. The bladder serves as a temporary storage reservoir for urine. In contrast, the lungs are primarily responsible for the exchange of gases, such as oxygen and carbon dioxide, during respiration and are not directly involved in the process of urine production.

3. Autoimmune diseases occur when the immune system mistakenly attacks healthy body tissues. What is a potential cause of autoimmune diseases?

A. Deficiency in essential vitamins and minerals
B. Exposure to environmental toxins
C. Breakdown in immune cell self-tolerance mechanisms
D. All of the above

Correct answer: C

Rationale: The correct answer is C. Autoimmune diseases are triggered by a breakdown in immune cell self-tolerance mechanisms, where the immune system fails to recognize 'self' from 'non-self' cells, leading to attacks on healthy tissues. While deficiencies in essential vitamins and minerals or exposure to environmental toxins can impact immune function, the root cause of autoimmune diseases is primarily attributed to the breakdown in self-tolerance mechanisms. This breakdown can be influenced by genetic predisposition, environmental factors, and other triggers, leading to the development of autoimmune conditions.

4. When sodium hydroxide (NaOH) reacts with hydrochloric acid (HCl), the resulting product is:

A. Hydrogen gas and sodium chloride (NaCl)
B. Chlorine gas and sodium oxide (Na2O)
C. Sodium metal (Na) and water (H2O)
D. No reaction occurs.

Correct answer: A

Rationale: This is a classic neutralization reaction, forming water and a salt (sodium chloride).

5. Which type of waves exhibit both longitudinal and transverse motion?

A. Electromagnetic waves
B. Surface waves
C. Mechanical waves
D. Sound waves

Correct answer: b

Rationale: Surface waves, like those on water surfaces, exhibit both longitudinal and transverse motion.

6. What is the functional group present in esters?

A. Hydroxyl
B. Carbonyl
C. Ester
D. Amine

Correct answer: C

Rationale: Esters have the functional group -COO-, representing a carbonyl group bonded to an oxygen atom. The other choices are associated with different functional groups.