Question

How the continuity of species is maitained generation after generation

Answer 1

if the species which is produced by reproduction is adaptable to the environment than the continuity of species is maintained generation after generation because the species which is adaptable to the environment gives rise to another young ones which is also adaptable to the environment (lamarkism) and in the same way further goes on

Answer 2

The continuity of species is maintained generation after generation by a process called reproduction.
Reproduction is a biological process in which an organism gives rise to young ones(offspring) similiar to itself. The offspring grows mature and in turn produce new offspring. So, there is a cycle of birth, growth and death.