1. What do the following cities have in common?

SANTA MONICA
KODIAK
ALBANY

2. What do the following partial words have in common?

AL
MAL
BEN
DES
RES

HINT:
2)
#1: The same three letters will change each word into a new one.
#2: The three letters are added to the end of each word.

Answers:

1. Each city ends with the two-letter US Postal Code of its state:

Santa Monica, CA
Kodiak, AK
Albany, NY

2. The letters IGN can be added to each word to change it into a new one:

ALIGN
MALIGN
BENIGN
DESIGN
RESIGN