The statement which best explains why carbon is present in so many kinds of molecules is because <u>it can form four covalent bonds.
<em /></u>It isn't rare on Earth, so A is incorrect. It has valence electrons, so C is incorrect. It cannot become an ion, so D is incorrect.<u>
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Answer: Option D " all of the above "
Explanation: DNA can be a great source of information when used as a forensic evidence. This technique has many advantages and disadvantages when used as a source of information in case of crime.
Identical twins: There are some common fragments of DNA that is same in identical twins so it can be a difficulty in deciding the criminal.
Not enough of a sample: DNA should be present in a detectable amount to be used an sample for evidence, less than this detectable amount is a waste and cannot be used as a sample for evidence.
Contaminated and degraded sample: If the sample of DNA is contaminated or degraded then the result might be incorrect and might not be used as a sample for forensic evidence.
Hence, the correct answers are all of the above.
I believe that the food web is more stable
The right answer is Lichen.
In ecology, a pioneer species is one of the first forms of life that colonize or recolonize a given ecological area.
Lichens are composite organisms resulting from a symbiosis between at least one heterotrophic fungus called mycobionte, representing 90% of all, and microscopic cells with chlorophyll (green algae or cyanobacteria autotrophic for carbon) called "photobionts" .
