1. The microscopic units responsible for muscle contraction are called

A. Neurons
B. Myofibrils
C. Tendons
D. Sarcomeres

Correct answer: D

Rationale: The correct answer is D: Sarcomeres. Sarcomeres are the fundamental contractile units of skeletal muscle. They are composed of overlapping actin and myosin filaments that slide past each other during muscle contraction, resulting in muscle shortening. Neurons (A) are nerve cells that transmit signals to and from the brain. Myofibrils (B) are thread-like structures within muscle fibers that contain sarcomeres. Tendons (C) are fibrous connective tissues that attach muscles to bones, but they are not directly involved in muscle contraction like sarcomeres are.

2. Which element has the same number of protons and neutrons?

A. Carbon (C)
B. Oxygen (O)
C. Lithium (Li)
D. Helium (He)

Correct answer: D

Rationale: Helium (He) - He-4 has 2 protons and 2 neutrons, while the other options have differing numbers.

3. The measurable electrical activity of the brain is recorded by a:

A. CAT scan
B. MRI scan
C. Electroencephalogram (EEG)
D. X-ray

Correct answer: C

Rationale: The correct answer is C: "Electroencephalogram (EEG)". An EEG is a non-invasive test that measures the electrical activity of the brain by placing electrodes on the scalp. It is specifically designed to record brain wave patterns, making it a valuable tool in diagnosing conditions such as epilepsy, sleep disorders, and brain injuries. A CAT scan (A) and MRI scan (B) are imaging techniques that show the structure of the brain, while an X-ray (D) is not typically used to measure brain electrical activity.

4. A children's toy consists of a half cylinder (diameter 10cm, height 8cm) attached to a cube with side lengths of 5cm. What is the total volume of the toy?

A. 125 cu cm
B. 200 cu cm
C. 275 cu cm
D. 350 cu cm

Correct answer: C

Rationale: Calculate the volume of the half cylinder and the cube separately, then add them up.

5. What is the name of the condition characterized by swelling caused by a buildup of lymph fluid?

A. Anemia
B. Edema
C. Hypertension
D. Diabetes

Correct answer: B

Rationale: The correct answer is B: Edema. Edema is the condition characterized by swelling caused by a buildup of lymph fluid in the body's tissues. Anemia (A) is a condition characterized by a lack of healthy red blood cells, not swelling. Hypertension (C) is high blood pressure, which does not directly cause swelling. Diabetes (D) is a metabolic disorder affecting blood sugar levels and does not directly lead to lymph fluid buildup and swelling.

6. Which part of the brain is responsible for regulating body temperature, hunger, and thirst, and is considered a key player in the endocrine system?

A. Amygdala
B. Hippocampus
C. Hypothalamus
D. Thalamus

Correct answer: c

Rationale: The correct answer is C: Hypothalamus. The hypothalamus is a small region in the brain that plays a crucial role in maintaining homeostasis by regulating body temperature, hunger, and thirst. It also serves as a key player in the endocrine system by controlling the release of hormones from the pituitary gland. The amygdala is responsible for processing emotions and memory, the hippocampus is involved in memory formation and retrieval, and the thalamus acts as a relay station for sensory information. Therefore, the hypothalamus is the most appropriate choice for the functions described in the question.