The clustered, regularly interspaced short palindromic repeats (crispr) system in bacterial cells has been called the "immune" system of bacteria. crispr protect bacteria from a repeat infection from the same phage because bacterial cells

By integrating the phase fragment in their own chromosome

Explanation:

The clustered regularly inter spaced short palindromic repeats are known as CRISP, found in the bacterial cell which acts as the immune system in case of bacterial cell.

These bacteria protect themselves from same infection twice by integrating the fragments from the phage DNA in their chromosomes and in case of further infection they recognize the fragment and prevents the cell from infection.

d. the weight of the book

well

explanation: