Maintaining organization and carrying on life requires outside source of energy. Food provides nutrient molecules used as building blocks or for energy. Metabolism is all chemical reactions that occur in a cell. Ultimate source of energy for life on earth is the sun through photosynthesis. Organisms must remain homeostatic or keep themselves stable in temperature, moisture level, acidity, and other physiological factors.
Response often results in movements of plant or animal.
Ability to respond helps organism survive. Responses to environment altogether constitute behavior of organism. Reproduction is the ability of an organism to make a copy of itself. Bacteria, protozoa, etc. simply split into two. Organisms develop as result of blueprint of instructions encoded in their genes.