1. Electroencephalography (EEG) measures electrical activity in the brain, primarily reflecting the activity of:

A. Neurons
B. Astrocytes
C. Oligodendrocytes
D. Microglia

Correct answer: A

Rationale: The correct answer is A: Neurons. Electroencephalography (EEG) measures the electrical activity in the brain, which is primarily generated by the neurons. Neurons are the main cells responsible for transmitting electrical signals in the brain, making them the key source of the brain's electrical activity. Astrocytes, oligodendrocytes, and microglia are important supporting cells in the brain but do not generate the electrical impulses that EEG measures. Therefore, the correct choice is A: Neurons.

2. What is the work done by a force of 20 N acting on an object that moves 5 meters in the direction of the force?

A. 100 Joules (J)
B. 25 Joules (J)
C. 4 Joules (J)
D. Work cannot be determined without knowing the object's mass.

Correct answer: A

Rationale: Work is defined as the force applied multiplied by the distance moved in the direction of the force. Work = force x distance = 20 N x 5 m = 100 J.

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. The liver plays a vital role in digestion. What is one of the main functions of the liver in the digestive system?

A. Physical breakdown of food
B. Production of digestive enzymes
C. Storage and processing of nutrients
D. Elimination of waste products

Correct answer: C

Rationale: The correct answer is C: 'Storage and processing of nutrients.' The liver is a crucial organ in the digestive system as it performs various functions such as storing nutrients like glucose, vitamins, and minerals, processing nutrients by converting them into usable forms for the body, and regulating their distribution to different parts of the body. While the physical breakdown of food primarily occurs in the mouth and stomach, and the production of digestive enzymes mainly happens in the pancreas and small intestine, the liver's main role is to manage and store the nutrients obtained from the digested food. Therefore, option C is the correct choice for the main function of the liver in the digestive process.

5. What is the unit of measurement for power?

A. Joule (J)
B. Newton (N)
C. Watt (W)
D. Kilogram-meter (kgÂ·m)

Correct answer: c

Rationale: Power is measured in watts (W) in the SI unit system.

6. Which type of wave requires a medium to travel through?

A. Electromagnetic waves
B. Mechanical waves
C. Sound waves
D. Both a and c

Correct answer: d

Rationale: Both mechanical waves (such as sound waves) and electromagnetic waves (like light) have different requirements for propagation, but both can travel through a medium.