The green patches on stagnant water bodies or ponds depict algae.

Chlorophyll is the chief component of algae. With the help of chlorophyll, the algae prepare their own food.

Nitrogen fixing bacteria are present in the root nodules of leguminous plants.

Nitrogen cannot be taken up by the plants directly from the atmosphere. Nitrogen from the atmosphere is converted into usable form by the nitrogen-fixing bacteria and then is taken up by the plants.

Fungi mainly constitutes for the saprophytes.

In the process of photosynthesis, the solar energy is converted into chemical energy.

Caustic potash absorbs carbon dioxide.

Fungi take their food in the form of solution.

This option is correct,  since the above mentioned are the examples of saprophytes.

Sporophytic is not a type of heterotrophic mode of nutrition.

Fungi basically grow in hot and humid weather.

Penicillin comes from a fungi.

Cuscuta is a parasitic plant.

Lichens are made of algae and fungi.

A lichen is a composite organism that arises from algae or cyanobacteria (or both) living among filaments of a fungus in a symbiotic relationship.

Haustoria are the parasitic roots of cuscuta plant.

Pitcher plant is a common example of insectivorous plant.

Rhizobium lives in a symbiotic relationship with the root nodules of leguminous plants.

Insectivorous plants grow in places which are deficient in nitrogen.

Mistletoe is not an example of insectivorous plant.