An anisotropic material:.a. is a material in which properties vary depending on which crystallographic direction the measurements are taken. b. is the area of atomic mismatch which exists between crystalline regions in the materials with different orientation or atomic arrangement. c. lacks systematic and regular arrangement of atoms over relatively large atomic distances. d. is composed of a collection of many small crystals.

is a material in which properties vary depending on which crystallographic direction the measurements are taken

Explanation:

An anisotropic material is one in which certain physical properties are different when measured in different directions. For example, wood is an anisotropic material. Its strength along the grains is different from that perpendicular to the grains. Single crystals that are not cubic are also anisotropic with respect to certain physical properties.

a is the best answer your welcome