Fill in the blanks:

(a) The insects, butterflies, honeybees and birds help flowering plants in [[1]] .

(b) A forest is a purifier of [[2]] and [[3]].

(c) Herbs form the [[4]] layer in the forest.

(d) The decaying leaves and animal droppings in a forest enrich the [[5]] .

Fill in the blanks are as follows:

(a) The insects, butterflies, honeybees, and birds help flowering plants in pollination.

(b) A forest is a purifier of air and water.

(c) Herbs form the lowest layer in the forest.

(d) The decaying leaves and animal droppings in a forest enrich the soil.