Molten Lava, and not solid like the crust.
DNA fragments are cut out restriction enzymes (restriction endonucleases) and then joined together using enzymes called DNA ligases.
<span>Restriction enzymes are enzymes which recognize target sequences (recognition sites) and cuts DNA at or near those sequences.</span>
DNA ligase is an enzyme that connects the gap between the molecules (if they have matching ends).
Mussels are molluscans and are freshwater animals. The change in the environment led to new traits of mussels, it underwent natural selection and the thick shells have high chances of survival.
<h3>What is natural selection?</h3>
Natural selection is a process of nature that eliminates the organism with less survival and unfit traits while selecting the organisms with better traits of survival in the altered conditions.
The arrival or the introduction of the crabs in the environment altered the previous habitat of the mussels and led to the adaptation of the better trait quality in the mussel species.
The trait of the thick shells underwent natural selection as they were favoured for the changed conditions. The mussel having thick shells have high chances of survival over thin-shelled mussels as the crab will find it hard to attack the thick-shelled mussels.
Therefore, option A. change in environment, option B. natural selection and option E. chances of survival are the correct statements.
Learn more about the natural selection here:
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