Final answer:
NHEJ can result in insertion or deletion mutations, making the statement false.
Step-by-step explanation:
The statement "NHEJ very rarely results in insertion or deletion mutations." is false. Non-Homologous End Joining (NHEJ) is an error-prone DNA repair mechanism that can result in insertion or deletion mutations. During DNA repair, if the broken ends of DNA are not aligned correctly, nucleotides can be added or removed, leading to insertions or deletions. These mutations can have significant effects on the functioning of genes and can be detrimental to the cell.