Answer:
Nucleotides are the subunits of DNA. The four nucleotides are adenine, cytosine, guanine and thymine. Each of the four bases has three components, a phosphate group, a deoxyribose sugar and a nitrogen-containing base.
Answer:
A. The magma cooled too quickly too quickly for gas to escape.
Explanation:
Scoria is a type of extrusive igneous rock. Some of their characteristics include that they cool quickly with no time for large crystals to form, some of them have large vesicles which are holes caused by gas bubbles when the lava was molten.