1. What is the waxy or oily substance produced by sebaceous glands that helps lubricate the skin and hair?

A. Keratin
B. Melanin
C. Sebum
D. Sweat

Correct answer: C

Rationale: The correct answer is C: Sebum. Sebum is a waxy or oily substance produced by the sebaceous glands in the skin. It helps lubricate and waterproof the skin and hair, preventing them from drying out. Keratin is a protein found in the skin, hair, and nails, providing structure and strength. Melanin is a pigment that gives color to the skin, hair, and eyes. Sweat is produced by sweat glands and helps regulate body temperature by cooling the skin through evaporation. In this question, sebum specifically refers to the substance produced by sebaceous glands, making it the correct answer.

2. What is the main function of the urinary system?

A. Transporting oxygen
B. Fighting off infections
C. Maintaining acid-base balance
D. All of the above

Correct answer: D

Rationale: The correct answer is D: 'All of the above.' The main function of the urinary system is not just limited to one specific task but encompasses multiple important functions. It is responsible for maintaining acid-base balance by regulating the pH of the blood through the excretion of acids and bases. Additionally, the urinary system plays a crucial role in filtering waste products from the blood and expelling them from the body, which helps in fighting off infections. Moreover, the urinary system is not involved in transporting oxygen, as this function is primarily carried out by the respiratory system. Therefore, 'All of the above' is the correct choice as it includes the comprehensive functions of the urinary system.

3. What is the difference between a prokaryotic cell and a eukaryotic cell?

A. Prokaryotic cells have a nucleus, while eukaryotic cells do not
B. Eukaryotic cells have a nucleus, while prokaryotic cells do not.
C. Prokaryotic cells have membrane-bound organelles, while eukaryotic cells do not.
D. Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.

Correct answer: B

Rationale: Rationale: - Prokaryotic cells are simpler and do not have a true nucleus. Their genetic material is located in the nucleoid region, which is not enclosed by a membrane. - Eukaryotic cells are more complex and have a true nucleus that houses the genetic material, enclosed within a nuclear membrane. - Both prokaryotic and eukaryotic cells have organelles, but eukaryotic cells have membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus, while prokaryotic cells lack these membrane-bound organelles.

4. hich word is most closely associated with the adjective "meticulous"?

A. careless
B. precise
C. indifferent
D. enthusiastic

Correct answer: B

Rationale: "Meticulous" implies carefulness and attention to detail, making "precise" its closest synonym.

5. A light ray travels from air (refractive index 1.00) into water (refractive index 1.33). What happens to its speed and direction?

A. Speed increases, direction bends towards the normal.
B. Speed increases, direction bends away from the normal.
C. Speed decreases, direction bends towards the normal.
D. Speed and direction remain unchanged.

Correct answer: A

Rationale: Due to the change in refractive index, the light ray bends towards the normal (water) as it slows down upon entering the denser medium.

6. What is the term for the reaction between an acid and a base to produce water and a salt?

A. Combustion
B. Neutralization
C. Oxidation
D. Decomposition

Correct answer: b

Rationale: Neutralization is the reaction between an acid and a base to produce water and a salt. The other choices do not accurately describe neutralization.