Question

The by-product of photosynthesis is
a. $CO_2$
b. $H_{2}O$
c. Glucose
d. $O_2$

Answer 1

Hint: Photosynthesis is the process of preparing the food in presence of sunlight, water by the plants, as the plants prepare the food on their own, so they are called photoautotrophs or primary producers of the ecosystem.

Complete answer:
- Plants use the process called photosynthesis, in order to make food.
- During photosynthesis, plants trap the light from the sun and utilize the energy of the light.
- Where this trapped light energy is used to convert to chemical energy and combine the water and carbon dioxide into glucose, which is used by the plants as their food.
- Where some energy is used to produce other substances such as cellulose and starch.
- Plants contain the special organelle called chloroplast, where it contains pigment chlorophyll a and chlorophyll b, Xanthanoids, and carotenoids, and this chlorophyll pigments absorb the blue light and red light from the daylight and reflects the green light.
- In the chloroplast, there are thylakoids which are arranged as stacks, in these thylakoids that light energy forms the glucose from water and $CO_2$.
- The plants get the carbon dioxide from the outer atmosphere through stomata, and water is absorbed by the roots of the plants and it is conducted to the leaves, and light is absorbed by the chlorophyll, so all this combines and forms the food and this process is called Photosynthesis.
- During this process, oxygen is liberated out to the atmosphere from the leaves as a byproduct.
- Other byproducts of the plants are sugars, such as glucose and fructose.

Hence, the correct answer is option (D).

Note: Photosynthesis occurs in two stages, one is light-dependent reactions and another one is light-independent reactions or dark reactions, and these dark reactions take place in the stroma of the chloroplast.