1. A new material is claimed to be stronger than steel. You design an experiment to test this claim. What is the MOST important control variable?

A. The size of the material samples.
B. The temperature at which the test is conducted.
C. The force applied to the material.
D. The color of the material.

Correct answer: A

Rationale: The size of the material samples is the most important control variable because it ensures that the comparison between the new material and steel is fair and accurate. By keeping the size consistent, any differences in strength can be attributed to the material composition rather than variations in sample size. Controlling for size helps eliminate confounding variables and increases the reliability of the experiment results. Temperature, force applied, and color are not as critical for directly testing the strength comparison between the new material and steel.

2. Which of the following is NOT a function of the endoplasmic reticulum (ER)?

A. Synthesis of lipids (fats)
B. Transport of materials within the cell
C. Detoxification of harmful substances
D. Breakdown of cellular waste products

Correct answer: C

Rationale: The correct answer is C: 'Detoxification of harmful substances.' The endoplasmic reticulum (ER) is responsible for synthesizing lipids (fats), transporting materials within the cell, and breaking down cellular waste products. However, detoxification of harmful substances is primarily carried out by the smooth endoplasmic reticulum (SER) where enzymes detoxify drugs and other harmful compounds. Therefore, C is the correct answer as it is not a primary function of the ER.

3. Which of the following functional groups is present in carboxylic acids?

A. Carbonyl
B. Hydroxyl
C. Carboxyl
D. Aldehyde

Correct answer: C

Rationale: Carboxylic acids contain the carboxyl functional group (-COOH). The other choices are associated with different functional groups.

4. The tonsils and adenoids are part of the lymphatic system located in the:

A. Chest cavity
B. Abdominal cavity
C. Head and neck region
D. Pelvic cavity

Correct answer: C

Rationale: The tonsils and adenoids are part of the lymphatic system and are located in the head and neck region. These structures help protect the body from infections by trapping pathogens that enter through the mouth and nose. The tonsils are located at the back of the throat, while the adenoids are located higher in the throat. They play a crucial role in the body's immune response, producing antibodies and helping to fight off bacteria and viruses that are inhaled or ingested. Therefore, the correct answer is C, the head and neck region.

5. What is the function of the pericardium, the sac surrounding the heart?

A. o generate electrical impulses for heart contraction
B. To transport blood throughout the body
C. To provide lubrication for heart movement
D. To protect the heart and anchor it in place

Correct answer: D

Rationale: The pericardium, the sac surrounding the heart, serves primarily to protect the heart and anchor it in place. It acts as a protective barrier against external infections or damage and helps to maintain the heart's position within the chest cavity. Additionally, the pericardium also provides some degree of shock absorption to minimize physical trauma to the heart. While the heart's electrical impulses for contraction originate from within the heart itself and are not generated by the pericardium, it does not play a role in directly generating these impulses. Therefore, option D, 'To protect the heart and anchor it in place,' is the correct function of the pericardium.

6. The unit for measuring luminous flux, which describes the perceived brightness of a light source by the human eye, is:

A. Candela
B. Lumen
C. Lux
D. Hertz

Correct answer: A

Rationale: The correct answer is B: Lumen. Luminous flux is the measure of the total quantity of visible light emitted by a source per unit time, measured in lumens. The candela (A) is the unit for luminous intensity, lux (C) is the unit for illuminance (luminous flux per unit area), and Hertz (D) is the unit for frequency. Therefore, in this question, the unit for measuring luminous flux is the lumen, as it specifically quantifies the perceived brightness of a light source by the human eye.