Chage identity of a substance
hope this helps
I do think that they close to not allow too much of either water or air from entering.
the hollow tube allows water to flow easily.
https://www.bbc.co.uk/bitesize/guides/z28g7p3/revision/1
In biology, the inner lining of tubular structures is called a lumen.
This can refer to numerous tubular structures in the body, such as the lumen of the veins and arteries, the lumen of the intestines or the tubes in the kidneys.
This term can also be used to describe a space defined by membranes of cell organelles such as the lumen of the mitochondria, the Golgi apparatus, and others.
Answer:
Keystone Species: Kangaroo Rat Keystone species are species whose presence and role within an ecosystem has a disproportionate effect on other organisms within the system. Hawk (predator)/lizard (prey). scorpion (predator)/insect (prey). if their is no relationship between these two then the scorpions will die off and the insects will thrive.
Explanation:
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Answer:
D) found in a limited time span
Explanation:
Index fossils are the remains of living organisms for which we have already established relative age. These are fossils that only existed during a limited period of geologic time and are easily identified, found in large volumes, and found in many different locations around Earth. Due to these factors, index fossils may be used as a guide for comparison in determining the relative age of an unknown object.
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