How do spores help sustain the population of ferns?

Spores do not have any natural predators.
There are million of spores that are made by a single plant to help keep its population.
Spores can hide under rocks for long time before maturing into an adult plant.
Spores can live for a long time without maturing into an adult plant.

The correct options are:

There are million of spores that are made by a single plant to help keep its population.

Spores can live for a long time without maturing into an adult plant.

Explanation:

Spores can be described as a means of reproduction in plants like the gymnosperms.

There are millions of spores produced by a single plant so that the chances of their dispersal and maturing into new plants is maximum.

Spores also have the capability to stay dormant until the conditions become favorable for the growth of a plant from the spore.

Another adaptation of spores is that they are light weight so that they can easily be carried away by the wind.

format change of dna.  

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.