10 Obsidian and pumice are extrusive igneous rocks and lack crystals. Why is it that these rocks
do not have crystals? *
(1 Point)
There were no minerals in the magma
The lava cooled slowly deep inside the Earth
The lava cooled too quickly above the Earth
The pressure was too great to make any crystals

Hi  to the mountain

Explanation:

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link: