The answer is 'Cambrian' explosion. This took place approximately 541 million years ago. 'Explosion' refers to the evolution of a large range of new major animal phyla. Scientists know this by the large number of diverse fossils from this period. Prior to this period, organisms were single-celled, but over the Cambrian Explosion, lasting about 80 million years, life forms diversified rapidly to resemble the life forms existing today.
Similarities
Both plant and animal cells have eukaryotic origins
Both have common organelles like the nucleus, mitochondria and ribosomes
Both are surrounded by a cell membrane
differences
plant cells have a regular defined shape while animal cells have an irregular shape
plant cells have a cell wall while animal cells lack a cell wall
plant cells have a chloroplast for photosynthesis while animal cells do not have a chloroplast
Answer:
Organisms decompose more quickly when they are in contact with oxygen. ... When an organism is buried quickly, there is less decay and the better the chance for it to be preserved. The hard parts of organisms, such as bones, shells, and teeth have a better chance of becoming fossils than do softer parts.
Explanation:
I would guess C, hope that helps!