Assertion : Staggered cut by restriction enzymes results in formation of sticky ends in DNA strands.

Reason : Stickiness of the ends facilitates the action of the enzyme DNA polymerase.

Assertion is true. When restriction enzymes cleave DNA, they can create two types of ends: blunt ends and sticky ends. Staggered cuts, also known as cohesive ends, result in the formation of sticky ends. Sticky ends are DNA ends with unpaired, single-stranded overhangs. These overhangs can base-pair with complementary sequences on another DNA molecule, which is why they are termed "sticky."

Reason is not true. Stickiness of the ends facilitates the action of the enzyme DNA ligase and not DNA polymerase.