Correct answer: A). Root
The part of the word that can not be broken down is called root word. In the word claustrophobic ''phob'' is the root word. It can not be suffix as a suffix are added after the root word. It cannot be prefixed as it is added before the root word. Here the prefix would be ''claustro'' and suffix would be ''ic''. It cannot be affixed as it contains both suffix and prefix.
Hence, the correct answer would be option A.
DNA ligase is an enzyme that repairs irregularities or breaks in the backbone of double-stranded DNA molecules. It has important role in the process of DNA replication and DNA repair. It has three general functions: It seals repairs in the DNA, it seals recombination fragments, and it connects Okazaki fragments (small DNA fragments formed during the replication of double-stranded DNA). DNA ligase functions by forming a bond between the end of a “donor” nucleotide and the end of an “acceptor” nucleotide.
.........................
