Correct Answer:
C. Carbon dioxide
Photosynthesis is a vital biochemical process that sustains most life on Earth. Plants, algae, and some bacteria use this process to convert light energy into chemical energy, producing food for themselves and oxygen for other organisms. Understanding the inputs and outputs of photosynthesis is crucial for comprehending basic biology and ecology.
- Carbon dioxide is the correct answer. Plants absorb carbon dioxide from the atmosphere through tiny pores called stomata on their leaves. This gas, along with water absorbed from the soil and energy from sunlight, is used in the chloroplasts to produce glucose (a sugar for energy) and oxygen as a byproduct.
- Helium is an inert gas and plays no role in the biological process of photosynthesis.
- Oxygen is a product of photosynthesis, released by plants into the atmosphere, not taken in for the process itself.
- Hydrogen is a component of water (H2O), which is absorbed by plants, but gaseous hydrogen is not directly taken in for photosynthesis.