1. What is the primary function of the epiglottis in the respiratory system?

A. Filtration of air
B. Production of mucus
C. Prevention of food entering the trachea
D. Oxygen exchange in the alveoli

Correct answer: C

Rationale: The primary function of the epiglottis in the respiratory system is to prevent food from entering the trachea. When we swallow, the epiglottis covers the opening to the trachea, directing food and liquids to the esophagus instead of the airway. This action helps to protect the respiratory system from foreign objects that could obstruct airflow and cause choking or aspiration pneumonia. Filtration of air and production of mucus are functions associated with other respiratory structures like the nasal passages and bronchial tubes, while oxygen exchange in the alveoli occurs in the lungs, not the epiglottis.

2. Polymers are

A. Large molecules formed by repeating units called monomers
B. Simple organic molecules with low boiling points
C. Highly reactive compounds used in industrial processes
D. Insoluble solids with no definite structure

Correct answer: A

Rationale: The correct answer is A: 'Large molecules formed by repeating units called monomers.' Polymers are macromolecules made up of repeating units called monomers, which are linked together through chemical bonds. This repetition results in long chains or networks of molecules, giving polymers their unique properties. Options B, C, and D are incorrect because polymers are not simple organic molecules with low boiling points, highly reactive compounds used in industrial processes, or insoluble solids with no definite structure. Understanding the basic definition of polymers helps us appreciate their wide range of applications in materials science, engineering, and everyday products.

3. Which form of energy is associated with the motion of an object?

A. Kinetic energy
B. Potential energy
C. Thermal energy
D. Electrical energy

Correct answer: a

Rationale: Kinetic energy is the energy of motion possessed by an object.

4. Which of the following is NOT a common site for lymph nodes?

A. Groin
B. Armpit
C. Neck
D. Liver

Correct answer: D

Rationale: The correct answer is D: 'Liver.' Lymph nodes are small, bean-shaped structures that are part of the lymphatic system. They are commonly found in areas such as the groin, armpit, and neck, where they help filter and trap harmful substances. The liver, while an important organ in the body, does not typically contain lymph nodes. Therefore, it is not a common site for lymph nodes. Understanding the locations of lymph nodes in the body is important for identifying potential sources of infection or cancer when assessing patients.

5. What is the basic unit of heredity?

A. Chromosome
B. Cell
C. Gene
D. Organ

Correct answer: C

Rationale: Rationale: A gene is the basic unit of heredity that carries the instructions for making proteins, which determine an organism's traits. Genes are segments of DNA located on chromosomes within the cell. While chromosomes contain many genes, a gene itself is the fundamental unit of heredity responsible for passing on genetic information from one generation to the next. Cells are the basic structural and functional units of living organisms, but genes specifically carry genetic information. Organs are composed of tissues and serve specific functions within an organism, but they are not the basic unit of heredity.

6. What is the name of the regulatory region in a gene that controls its expression?

A. Exon
B. Intron
C. Promoter
D. Enhancer

Correct answer: C

Rationale: Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression. B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression. C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression. D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter. Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.