The formation of new organisms is called

The formation of new organisms is called reproduction.

Explanation: Reproduction is of following two types :

1) Asexual reproduction : In this type of reproduction a new organism developed without the involvement of other ogranism that means only by the single parent.

2) Sexual Reproduction : In this type of regards formation of new organism done by the involement of two different sex organisms. By the fusion of female egg and male sperm.

Reproduction has great importance for organism itself and also in field of evolution. By the process of reproduction when two different individuals reproduce and create new organism or offsprings , they create new characteristics. The new characteristics has evolutionary values. Because all the new characteristics helps organisms in their survival.

Also sexual reproduction helps organism in continuing their breeds , their features , characteristics.

for a different answer set the answer would be because the oxygen in the water had depleted (apex)