They are called eukaryotes.
It is true that earth is consist of 70% water. However it is still a problem that in the near future, their might be a water shortage that will happened. This is because now mostly of our water sources are no longer clean. Our water are polluted and when time will come water will be very pricey
Species is the most narrow category
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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.
2. To focus a microscope using the high power lens you must first in low power center the specimen and make sure it is in focus. Then switch to high power and adjust using the fine adjustment or the smaller knob.
3. It prevents dust from settling on the scope and in the lenses.
