1. Insulin, a hormone responsible for regulating blood sugar levels, is produced by the:

A. Parathyroid gland
B. Pancreas
C. Thymus gland
D. Ovaries

Correct answer: B

Rationale: The correct answer is B: Pancreas. Insulin is a hormone that plays a crucial role in regulating blood sugar levels by allowing cells to take in glucose from the bloodstream. The pancreas is an organ located near the stomach that contains clusters of cells called islets of Langerhans, which are responsible for producing insulin. The parathyroid gland, option A, regulates calcium levels in the blood. The thymus gland, option C, is involved in the development of the immune system. The ovaries, option D, produce hormones like estrogen and progesterone but not insulin. Therefore, the pancreas is the correct gland responsible for producing insulin.

2. When an atom gains or loses electrons, it becomes a(n):

A. Molecule
B. Isotope
C. Ion
D. Compound

Correct answer: C

Rationale: Gaining or losing electrons alters the atom's electron count and charge, creating a positively or negatively charged ion.

3. How many bones are there in the adult human skeleton?

A. 126
B. 206
C. 300
D. 525

Correct answer: D

Rationale: The correct answer is D: 525. The adult human skeleton consists of 206 bones. However, when accounting for individual bones, many of them are paired (like the ribs and vertebrae), bringing the total count to 206 individual bones but 525 in total when considering pairs. This includes bones in the skull, spine, ribs, arms, hands, pelvis, legs, and feet. So, while there are 206 individual bones, the total number of bones in the adult human skeleton is 525 when considering pairs.

4. The least common multiple (LCM) of two numbers is the smallest number that is a multiple of both. Which of the following represents the LCM of 14 and 21?

A. 42
B. 63
C. 84
D. 168

Correct answer: C

Rationale: We can list out the multiples of each number until we find a common multiple. 14, 28, 42, 56, 84, ... 21, 42, 63, 84, ... The least common multiple is 84.

5. Identify the preposition in the following sentence: The cat jumped over the fence.

A. cat
B. jumped
C. over
D. the

Correct answer: C

Rationale: Prepositions show the relationship between a noun or pronoun and another word in the sentence. "Over" indicates the position of the cat in relation to the fence.