Question 77

Plants require carbon dioxide to produce sugars through photosynthesis.

Photosynthesis is the process by which plants convert carbon dioxide and water into sugars and oxygen, using sunlight as energy. Thus, carbon dioxide is essential for this process.

A) Nitrogen

Nitrogen is an important nutrient for plants, primarily used to synthesize amino acids and proteins. However, it is not directly involved in the photosynthesis process for producing sugars, making this option incorrect.

B) Oxygen

Oxygen is a byproduct of photosynthesis, produced when plants convert carbon dioxide and water into sugars. While it is crucial for respiration in many organisms, it is not a gas that plants require to carry out photosynthesis, thus rendering this option incorrect.

C) Carbon dioxide

Carbon dioxide is the key atmospheric gas that plants utilize in photosynthesis. It combines with water to produce glucose and oxygen, making it the correct answer as it is fundamentally necessary for the production of sugars.

D) Helium

Helium has no role in biological processes such as photosynthesis. It is an inert gas that does not participate in the chemical reactions involved in the production of sugars in plants, making this option incorrect.

Conclusion

Carbon dioxide is unequivocally the gas that plants need for photosynthesis, as it is directly involved in the synthesis of sugars. Options A, B, and D do not fit the requirement for photosynthesis, as they either serve different roles or are not utilized in this critical process. Thus, option C is the only correct choice.