3. what 20th century discovery has been instrumental to the field of genetic engineering by allowing researchers to cut and splice specific dna fragments into microorganisms?
a) small rnas
b) restriction enzymes
c) ribozymes
d) the microbiome

b) Restriction enzymes

Explanation:

Restriction enzymes are the endonucleases that recognize and cut the specific DNA sequence and breakdown the DNA into smaller fragments.

With the discovery of these enzymes, it became possible to cut the genome of microbes or any other organism at the specific site.

For example, the restriction sequence for the restriction enzyme EcoRI is 5' GAATTC 3' on one strand and it cuts between G and A of the sequence and between A and G on the complementary strand.

which

what is a measurement of the earth’s history divided into time periods?

> fossil record <

sedimentary rock

> geologic time scale <

radioactive elements