The appearance of fossils would the the answer.
Although there has been some scientific debate about what fossil strata should mark the beginning of this period, the "International Geological Congress" determined that the Cambrian period was approximately 543 million years ago of which the first appearance in the fossil record of worms that made horizontal burrows was discovered.
Answer:
zika is a parasite
Explanation:
this is a common parasite but if you want my personal opinion, the parasite is none of these, its my younger brother.
The answer is B: Water breaks down into oxygen molecules for respiration.
Answer:
They speed up chemical reactions. Without them you wouldn't be alive. They break down macromolecules, and also lower the amount of energy needed for a chemical reaction to happen.
I'd say
B. Contour Farming
since it's planting on a flat surface and creating w/ridges to help prevent water from taking the crops away