Agroup of stars, gas, and dust held together by gravity is a
a.
galaxy
c.
local group
b.
constellation
d.
both a and b

What are the 3 types of artificial cloning

Why do some dna fragments move farther than others during gel electrophoresis? a. because their shapes are different b. because they are different types of molecules c. because the samples are different colors d. because their masses are different

How do ratio scale and diagrammatic scale work