What are the benefits of photosynthesis?
a. all answers are correct
b. it begins all food chain
c. it makes organic molecules like sugar
d. it produces oxygen gas

The correct option is 'a': All the answers are correct.

Explanation:

Since plant's are abundant and can manufacture their own food hence they serve as the beginning of all the food chains hence option 'b' is correct.

In the process of photosynthesis the plants make use of carbon dioxide, sunlight , water, in presence of a pigment called chlorophyll present in plant cells in organelles called as plastids to yield glucose which is a carbohydrate or simplest sugar and release oxygen into the atmosphere. Hence options 'c' and 'd' are also correct.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.