Question

In what way can DNA segments be changed such that genes are altered or mutated?

Answer 1

Answer;

All the three are correct

• New DNA segments can be inserted.
• New DNA segments can be substituted.
• DNA segments can be deleted.

Explanation;

• DNA are important molecules that carry hereditary information in all organisms. The nucleotide sequences or the genes are subject to change as a result of mutations.
• Mutations are spontaneous random changes that occur in the genetic make up of an organisms or the DNA sequences of an organism.
• When mutations occur they can cause insertion of new DNA segments, substitution of DNA sequences with new ones, and also deletion of some sequences of DNA.
• Substitutions, deletions and insertion mutations are types of mutations that affect cells at gene level.  

Answer 2

That would be I, II, and III 

I and II will cause a frame shift mutations. 
II can cause horrible effects if the substituted base codes for a stop codon.