1. What is the protective fluid that surrounds the brain and spinal cord?

A. Blood
B. Cerebrospinal fluid
C. Myelin sheath
D. Insulin

Correct answer: B

Rationale: The correct answer is B: Cerebrospinal fluid. This fluid acts as a cushion for the brain and spinal cord, providing protection from impacts. Blood is essential for transporting nutrients and oxygen, but it does not directly surround or protect these vital nervous system structures. Myelin sheath is a fatty substance that insulates nerve fibers, not the fluid surrounding the nervous system. Insulin is a hormone involved in regulating blood sugar levels and is not related to protecting the brain and spinal cord.

2. What happens during a physical change in matter?

A. A new substance with different properties is formed
B. The chemical composition of the substance changes
C. The original substance can be recovered by physical means
D. Energy is either released or absorbed

Correct answer: C

Rationale: During a physical change in matter, the original substance undergoes a change in its physical state or appearance without any change in its chemical composition. This means that the original substance can be recovered by physical means, such as melting, freezing, boiling, or condensing. No new substance is formed (option A), the chemical composition remains the same (option B), and energy changes can occur but are not a defining characteristic of a physical change (option D).

3. Which word best completes the sentence: "The scientist conducted the experiment with _____ precision."

A. extreme
B. great
C. utter
D. remarkable

Correct answer: C

Rationale: Option C emphasizes the absolute and complete accuracy of the experiment.

4. The ball-and-socket joint, which allows for wide range of motion, is found in the connection between:

A. Upper arm and shoulder blade (scapula)
B. Collarbone (clavicle) and breastbone (sternum)
C. Two vertebrae in the spine
D. Ribs and sternum

Correct answer: A

Rationale: The correct answer is A: 'Upper arm and shoulder blade (scapula).' The ball-and-socket joint is found in the connection between the humerus (upper arm bone) and the scapula (shoulder blade). This joint allows for a wide range of motion, including flexion, extension, abduction, adduction, and rotation. The collarbone (clavicle) and breastbone (sternum) are connected by a cartilaginous joint, not a ball-and-socket joint. Two vertebrae in the spine are connected by facet joints, and the ribs and sternum are connected by cartilaginous joints and the costovertebral joints. Therefore, the ball-and-socket joint is uniquely found in the connection between the upper arm and the shoulder blade, allowing for the shoulder's impressive range of motion.

5. What is the term for a solution that has exactly the same concentration of solute as another solution?

A. Saturated solution
B. Unsaturated solution
C. Isotonic solution
D. Concentrated solution

Correct answer: c

Rationale: An isotonic solution has the same concentration of solute as another solution. The other choices do not accurately describe an isotonic solution.