1. Maintaining good muscle strength and flexibility as we age becomes important to avoid:

A. Headaches
B. Falls
C. Anxiety
D. Common cold

Correct answer: B

Rationale: The correct answer is B: 'Falls.' Maintaining good muscle strength and flexibility as we age is crucial for preventing falls, which become more common with age and can lead to serious injuries such as fractures. Strong muscles and good flexibility help in maintaining balance and stability, reducing the risk of falls. Headaches, anxiety, and the common cold are not directly related to muscle strength and flexibility, making them less likely to be avoided by focusing on these aspects of physical health.

2. Which of the following is NOT a method of sterilization?

A. Autoclave
B. UV light
C. Chemical disinfectants
D. Boiling water

Correct answer: D

Rationale: Rationale: A) Autoclave: An autoclave is a method of sterilization that uses high pressure and steam to kill microorganisms, making it an effective way to sterilize equipment and materials. B) UV light: UV light is a method of sterilization that damages the DNA of microorganisms, preventing them from reproducing and causing infections. C) Chemical disinfectants: Chemical disinfectants are used to kill or inactivate microorganisms on surfaces, but they may not always achieve sterilization, which is the complete destruction of all microorganisms. D) Boiling water: Boiling water is a method of disinfection rather than sterilization. While boiling water can kill many microorganisms, it may not be effective against all types of bacteria, viruses, and spores, making it unsuitable for achieving sterilization. Therefore, the correct answer is D) Boiling water, as it is not a method of sterilization

3. What is the relationship between the speed of a wave, its frequency, and wavelength in a given medium?

A. Speed = Frequency Ã— Wavelength
B. Speed = Frequency Ã· Wavelength
C. Speed = Frequency + Wavelength
D. Speed = Frequency - Wavelength

Correct answer: a

Rationale: In a given medium, the speed of a wave equals the product of its frequency and wavelength.

4. Which structure in the respiratory system is responsible for preventing food and liquids from entering the trachea during swallowing?

A. Bronchi
B. Larynx
C. Alveoli
D. Pharynx

Correct answer: B

Rationale: The correct answer is B: Larynx. The larynx, also known as the voice box, is a crucial structure in the respiratory system responsible for preventing food and liquids from entering the trachea during swallowing. It contains the epiglottis, a flap of tissue that covers the trachea during swallowing to ensure that food and liquids are directed to the esophagus instead of entering the airway. The bronchi are the two main branches that carry air into the lungs, while alveoli are tiny air sacs where gas exchange occurs. The pharynx is a shared pathway for both air and food, located behind the oral and nasal cavities. Therefore, the larynx plays a vital role in protecting the respiratory system during swallowing.

5. Isotopes are variants of a single element that differ in:

A. Having the same number of protons but varying numbers of neutrons
B. Having the same number of neutrons but varying numbers of protons
C. Having the same mass but different atomic numbers
D. None of the above

Correct answer: A

Rationale: The correct answer is A: 'Having the same number of protons but varying numbers of neutrons.' Isotopes are atoms of the same element with the same number of protons (which determines the element) but different numbers of neutrons. This results in isotopes having slightly different atomic masses. Options B and C are incorrect because isotopes specifically refer to variations in the number of neutrons, not protons or atomic numbers. Option D is incorrect because isotopes do exist due to differences in neutron number.

6. Which of the following is an example of an unsaturated fatty acid?

A. Stearic acid
B. Palmitic acid
C. Oleic acid
D. Butyric acid

Correct answer: C

Rationale: Oleic acid is an unsaturated fatty acid, containing at least one double bond in its hydrocarbon chain. The other choices are saturated fatty acids.