Crystals are substances with a regular, repeating arrangement of atoms. You can see this clearly in any image you get of any crystalline formation.
You can get this answer, either by knowledge or elimination. Some terms cannot even have atoms (atomic number, buffer, etc.), others aren't even substances (chemical bond, chemical reaction, covalent bond, pH) and yet others are so small atoms don't fit in them (proton, neutron).
Image description: Crystalline formation - differences with other formations.
Hope it helped,
BioTeacher101
Answer:
Parabolic dunes
Explanation:
A parabolic dune is a U-shaped mound of sand. The tips point upwind because they are anchored by vegetation.
A is wrong. The tips of a barchan dune point downwind
C is wrong. A longitudinal dune is parallel to the prevailing wind.
D is wrong. The ridge of a transverse dune is perpendicular to the prevailing wind.
