1. Why is it important to have control groups in scientific experiments?

A. To please funding agencies and research institutions.
B. To showcase the researcher's ingenuity and creativity.
C. To allow comparison and isolate the effect of the variable being tested.
D. To provide additional data points for statistical analysis.

Correct answer: C

Rationale: Control groups allow observation of what would happen without the tested variable, giving a baseline for comparison and isolating the specific effect being studied.

2. Which process involves the body's natural defense against inhaled dust and allergens?

A. Cellular respiration
B. Gas exchange
C. Ciliary action
D. Bronchoconstriction

Correct answer: C

Rationale: The correct answer is C: Ciliary action. Cilia are tiny hair-like structures lining the respiratory tract that help trap and remove inhaled dust and allergens. When these particles are trapped in the mucus produced by the cilia, the cilia beat in a coordinated fashion to move the mucus and its trapped particles out of the respiratory system, preventing them from reaching the lungs. Cellular respiration (A) is the process by which cells generate energy from nutrients, not a defense mechanism. Gas exchange (B) refers to the exchange of oxygen and carbon dioxide in the lungs, not a defense mechanism. Bronchoconstriction (D) is the narrowing of the airways, often in response to triggers like allergens, but it is not the body's natural defense mechanism against inhaled dust and allergens.

3. Which of the following is the main function of the small intestine?

A. To store food and break it down into smaller pieces
B. To absorb nutrients into the bloodstream
C. To produce enzymes that help digest food
D. To eliminate waste products from the body

Correct answer: B

Rationale: Rationale: The small intestine is a crucial part of the digestive system where the majority of nutrient absorption takes place. It is lined with tiny finger-like projections called villi that increase the surface area for absorption. The small intestine absorbs nutrients such as carbohydrates, proteins, fats, vitamins, and minerals from the digested food into the bloodstream to be transported to cells throughout the body for energy, growth, and repair. Options A, C, and D do not accurately describe the main function of the small intestine.

4. Which of the following phases of mitosis is characterized by the separation of sister chromatids and their movement to opposite poles?

A. Metaphase
B. Anaphase
C. Anaphase
D. Cytokinesis

Correct answer: B

Rationale: Rationale: During anaphase of mitosis, the sister chromatids, which are duplicated copies of a chromosome, separate and move towards opposite poles of the cell. This movement is facilitated by the shortening of microtubules attached to the chromatids. As a result, each pole of the cell receives a complete set of chromosomes, ensuring that the daughter cells produced after cell division will have the correct number of chromosomes. Metaphase is characterized by the alignment of chromosomes at the cell's equator, not their separation. Telophase is the phase following anaphase, where the separated chromatids reach the opposite poles and nuclear envelopes start to form around them. Cytokinesis is the final stage of cell division, where the cytoplasm is divided to form two separate daughter cells.

5. Which of the following numbers is NOT divisible by 3?

A. 105
B. 141
C. 273
D. 810

Correct answer: D

Rationale: Rationale: To determine if a number is divisible by 3, we can check if the sum of its digits is divisible by 3. If the sum of the digits is divisible by 3, then the original number is also divisible by 3. A) 105: 1 + 0 + 5 = 6, which is divisible by 3. Therefore, 105 is divisible by 3. B) 141: 1 + 4 + 1 = 6, which is divisible by 3. Therefore, 141 is divisible by 3. C) 273: 2 + 7 + 3 = 12, which is divisible by 3. Therefore, 273 is divisible by 3. D) 810: 8 + 1 + 0 = 9, which is divisible by 3. Therefore, 810 is divisible by 3. Since all the

6. What is the process by which a fertilized egg implants itself in the lining of the uterus?

A. Fertilization
B. Implantation
C. Gestation
D. Parturition

Correct answer: B

Rationale: The correct answer is B: Implantation. Implantation is the process by which a fertilized egg, or zygote, attaches itself to the uterine wall to establish a pregnancy. Fertilization is the fusion of sperm and egg to form a zygote, which occurs in the fallopian tube. Gestation refers to the period of development of the fetus inside the uterus. Parturition is the process of giving birth. Therefore, implantation specifically refers to the attachment of the fertilized egg to the uterine lining, making it the most appropriate answer in this context.