Answer: Layer a is 500 million years old.
Explanation:
Trilobite is a member of the group of extinct arthropods found as fossils and they can be identified by the three-lobed as well as three segmented forms. These were the marine animals. These were appeared initially in the Cambrian Period. They used to live 542 million years ago so the fossils can be estimated to be aged of 500 above years old. These animals used to dominate in the sea area.
The correct answer is meiosis. This is because a zygote is a 2n diploid cell caused by human fertilization witch is meiosis. This shows that the correct answer is meiosis. There are two things needed witch are the two gametes. These two gametes are called the egg(female) and the sperm(male).
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Activation energy is the minimum quantity of energy that the reacting species must possess in order to undergo a specified reaction.
for example , striking a match on the side of a matchbox provides the activation energy, in the form of heat produced by friction.
Secretary of defense is ahead but not a soldier in rank
In ranking its the general (which is the highest rank in the army)
Acetylcholine (ACh)
Acetylcholine is an organic chemical that functions in the brain and body of many types of animals as a neurotransmitter.
