Green plants and green sulphur bacteria,which prepare their organic food themselves with the help of sunlight,are known as:

Select the incorrect statement.

Select the correct option regarding photosynthesis.

Select the correct option:
$(1)$ $C_4$ plants have double the efficiency of carbon fixation compared to $C_3$ plants.
$(2)$ Sugar is transported from source to sink through the $\text{phloem}$ / $\text{xylem}$ tissue.

Why do fishes in an aquarium thrive better if green plants are growing there?

Give a comparison between the following:
$(a)$ $C_{3}$ and $C_{4}$ pathways
$(b)$ Cyclic and non-cyclic photophosphorylation
$(c)$ Anatomy of leaf in $C_{3}$ and $C_{4}$ plants