Areef results from life processes. true false

A reef results from life processes: True

Yes, if it is an organic reef. However, contrary to the other answer, reefs are built by many liviing organisms, not just corals (cnidarians), and most coral reefs have a large number of other organisms that contribute significantly to building the reef. Modern coral reefs are composed of 40-80% coral, with the other primary component being calcareous algae. In some instances calcareous algae compose almost all of the reef. Many other organisms inhabit the reef and contribute to its build-up such as bryozoans, encrusting molluscs, and even microbes which often cement particles together. Other types of organisms do build reefs too. Oysters build reefs in some modern oceans.

Mitochondria produce atp, a high energy compound. atp is used for all sorts of enzyme-mediated reactions, such as making proteins/nucleotides/etc, certain compounds cross the cell membrane, muscles move, etc.  without this source of energy, a cell will die. it will not be able to repair itself, defend against pathogens, etc.