Read the following statements.

I. Interaction between hormones and certain environmental factors regulate the reproductive processes and the associated behavioural expression of organisms.

II. In animals, but not in plants, hormones are responsible for the transitions between juvenile, eproductive and senescent phases.

III. After attainment of maturity, all sexually reproducing organisms exhibit events and processes that have remarkable fundamental similarity, though the structure associated with sexual reproduction are indeed very different.

IV. The post-fertilisation events include gametogenesis and gamete transfer.

V. In majority of the sexually reproducing organisms, the gametes produced are morphologically distinct types, i.e. heterogametes.

Which of the above statements are correct?