The correct option is C Hormones
In both plants and animals, hormones are directly responsible for the transitions between juvenile, reproductive and senescent phases. It involves interaction between hormones and certain environmental factors. This helps regulate the reproductive processes and the associated behaviours in organisms.
Food is essential for the normal and proper growth of the organism. Enzymes are required for the various metabolic activities that take place in an organism. However, these are not directly involved in the transitions between juvenile, reproductive and senescent phases in organisms.