<span>Plants take in oxygen all the time for respiration.
Photosynthesis which begins by combining water and CO2, continues in the
"dark phase" in making the glucose molecule. Light is not used for this
part of the reaction so it is called dark , because light is needed for
the first part.
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Commonly, genes from bacteria are inserted into a crop's chromosomes to produce pesticide substances to kill insects
For drought, I'm not fully sure, but Maize is a very drought resistant crop often introduced to communities which receive little rainfall. Maybe they take a gene from the maize crop and insert it into the chromosomes
The original location of an earthquake is known as the epicenter.
What are the other answers?
I do not think it is A.
Is Simmering an option?