Answer: A.
Explanation: When a chlorine atom gains an electron, its outermost principal energy level achieves an octet. In this case, the ion has the same outermost shell as the original atom, but now that shell has eight electrons in it.
The answer is <span>-Only the few bacteria that were immune to the antibiotic survived and reproduced, making all their offspring immune to it as well.
Bacteria (or any other organism) are not able to make changes to their DNA in order to protect themselves or to learn to remove the receptors on their cell surfaces. If they were able to produce toxins against the antibiotics, they would all survive.
These leave the second choice as the correct answer. This is the real situation, and is a good example of natural selection.</span>
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Answer: c
Explanation:
the roots absorb water and minerals from the soil and anchor the plant in the ground.
Water,Nitrogen, phosphorus and carbon are items that are cycled through the biosphere in biogeochemical cycles.
Explanation:
- Biogeochemical cycles maintain the balance of elements and compound in nature.
- These help the chemical substances to circulate through different spheres of the earth.
- They are, water cycle, sulphur cycle Nitrogen cycle, Carbon cycle ,Phosphorus cycle etc.
- If the biogeochemical cycles were not present then elements such as nitrogen , phosphorus carbon should have got completely used up instesad of getting replenished. Thus, making several metabolism stagnant.