Because the cell surface membrane may not want it to come into the cell or go out.
The cell surface membrane is what controls what flows in and out of a cell.
Explanation:
As an ecosystem changes,older inhabitants gradually die out and new organisms move in,causing further changes in the community.This series of predictable changes that occurs in a community over time is called ecological succession.Ecological succession is slow and gradual ;it occurs over a period of many years.
I hope this helps!
The answer is B.Normal vision and Vitamin A
If we guide ourselves with the Moh´s scale:
Material scratches apatite → material is harder than 5.
Material is scratched by corundum → material is softer than 9.
Conclusion:
The hardness of the unknown material stands between 5 and 9.
Note:
Both apatite and corundum are defining materials (reference materials in the Moh´s scale). So, you can also give an answer using defining materials:
"It can either be an orthoclase feldspar, a quartz or a topaz".
Hope it helped,
BiologiaMagister
<u><em>This answer is dedicated to JaySL</em></u>
Answer:
A,C and D
Explanation:
I could be wrong but I believe its correct