in animals the juvenile phase is followed by ....1] death 2] senescence phase 3] maturation phase 4] reproductive phase

let me make it clear that life span is divided into 3 parts

1. juvenile phase-period in which invidual growth takes place and attains maturity too.

2. reproductive phase - when the reproductive organs become functional  i.e. when the organs starts producing gametesor produce similar cpies 

3. senescence phase - the phase of deterioration i.e.getting old and finally death occurs