A DNA segment removed from neurospora

(a pink mold) contained the base sequence

G-T-C-C-A-T-G-C-A. A similar segment of

DNA removed from neurospora that had been

exposed to radiation for several hours had the

base sequence G-T-C-C-A-T. This change in the

base sequence is an example of

(1) a deletion (3) a substitution

(2) an insertion (4) a replication