Each cell is alive even if it is part of a multi celled body, and all living organisms consist of one or more cells. Also, cells reproduce by dividing so it follows that all existing cells must have arisen by division of other cells. As a cell divides it passes it hereditary material- its DNA- to offspring.
DNA (or deoxyribonucleic acid) is the molecule that carries the genetic information in all cellular forms of life and some viruses. Source-
DNA, Genes and Chromosomes — University of Leicester
www2.le.ac.uk/projects/vgec/highereducation/topics/dna-genes-chromosomes
In the open ocean, especially around the surface, one of the main sources of food for fish would be the algae that grow at the surface & photosynthesize with the sun. Without fish to regulate the amount of surface algae, they overgrow and block the sun from the organisms on the coral reef.
Without sun, the reef is not able to sustain themselves & it's down hill from there.
I hope this helps!
Conjugation - this is when bacteria exchange genes among each other. Sexual reproduction is when genes from the male and female are fused to create a new diverse zygote. Bacteria can do a similar process by conjugation.<span />