Final answer:
Chlorofluorocarbons have indeed been banned by many countries because they are harmful to the ozone layer, not beneficial as stated in the reason provided. The pupil of the eye narrows in bright light to protect the retina by reducing the amount of light that enters. Athlete's shoes have spikes to increase friction and prevent slipping, accurately explaining their purpose. Option A is the correct answer.
Step-by-step explanation:
In the context of the provided assertions and reasons, the correct answers can be deduced through logical reasoning and understanding of the phenomena involved. The first assertion (A), "Chlorofluorocarbons have been banned by many countries," is indeed true. Chlorofluorocarbons (CFCs) are known to have damaging effects on the ozone layer, which protects the Earth from harmful ultraviolet radiation. Countries around the world have agreed to phase out their use under the Montreal Protocol due to these detrimental environmental impacts. Therefore, the reason (R) given, "Chlorofluorocarbons are very good for the ozone layer," is false. CFCs actually result in the depletion of the ozone layer, contrary to what is stated in the reason. Thus, the correct answer is (c) (A) is true but (R) is false.
The second assertion states, "The pupil of the eye becomes narrow in bright light." This is a true statement as it is a biological response known as the pupillary light reflex. The reason (R) given, "This reduces the amount of light entering the eye," is also true and is the correct explanation for why the pupil constricts in bright light. Reducing the intensity of light protects the sensitive retinal cells in the eye. Hence, the correct answer to this statement is (a) Both (A) and (R) true, and (R) is the correct explanation of the (A).
For the third statement, the assertion (A), "The shoes of athletes are provided with special spikes," is true. These spikes are used in certain sports such as track and field to provide better traction on the surface, thereby improving an athlete's performance. The reason (R), "The spikes increase the friction so that the athlete doesn't slip," is also true and is the correct explanation for the inclusion of spikes in the shoes of athletes. Increasing friction between the shoe and the ground surface prevents slipping and enhances the athlete's grip and stability during movement. The correct answer, therefore, is (a) Both (A) and (R) true, and (R) is the correct explanation of the (A).