Final answer:
a. deletion of a single base. b. substitution of one base with a different base. A point mutation can cause deletion of a single base, substitution of one base with a different base, or frameshift mutation if the reading frame is affected.
Step-by-step explanation:
A point mutation can cause a deletion of a single base, a substitution of one base with a different base, or a frameshift mutation if the reading frame is affected. In the case of a deletion, if one base is removed from the DNA sequence, it can disrupt the reading frame and change the set of codons. Substitution occurs when a single base is replaced by a different base, which can result in a different amino acid being incorporated into the protein. Translocation of whole regions of a chromosome is not caused by a point mutation.