Earth’s period of a 24 hour day is based on? 1.mythological characters
2.the time it takes for the Sun to appear in the same position
3.the time it takes Earth to rotate once
4.moon phases

3. the time it takes for Earth to rotate once

Explanation:

science-ocean floors and habitats study guide by volleyballqueen3817 a major advance in ocean-floor mapping. list four sections of the ocean floor. algae that use sunlight to produce their own food through photosynthesis. all of the feeding relationships that exist in a habitat. drying out, predators, find food.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).