The sentence “they save energy and metabolites and help the organisms to respond to the environmental changes” characterizes the regulatory mechanisms of gene expressions in organisms. The correct answer between all the choices given is the second choice or letter B. I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.
Answer: definitely C will help you
Explanation:
Earth<span> can be divided into three main </span>layers<span>: the core, the mantle and the crust
Your answer would be, Core.
(Could also be called inner core)
Think of it as a watermelon, you have the crust, which is the green part, the mantle which is the whitish green part and the red which is the core.
Hope this helps.
In case you didn't get any of that, the answer is Core</span>
First fill in the blank: Restriction enzymes (restriction endonucleases)
Second fill in the blank: Restriction sites