Two physical properties of minerals both result in smooth, flat surfaces with specific angles between them. The first property is externally visible and is the result of how the mineral forms; the second is inherently internal and is the result of breaking a sample of the mineral. These properties are called .a. hardness and cleavage.
b. cleavage and hardness.
c. crystal habit and cleavage.
d. cleavage and crystal habit.

c. crystal habit and cleavage.

Explanation:

Minerals are solid substance , inorganic and natural occurring substance that have a definite chemical formula and structure. Mineral have various physical characteristics that can be noticed example are color, streak, crystalline habit, cleavage(fracture) , hardness, tenacity etc.

Crystal habit is the external shape of a mineral displayed by the composition of the crystals. The crystal habit of a mineral is the tendency of a mineral to grow into various shape. The crystal habit can be affected by the atomic structure of the mineral or even the environment in which it grows. The crystal of the mineral grows to give it a visible shape. This shape invariably give information on the kind of mineral present. Generally, the crystal habit is externally visible.

Cleavages refers to the tendency of minerals to break according to some certain line of weakness. The properties is inherently internal, because the line of weakness is due to the kind of bonding present in the mineral. The tendency of this mineral to break along a definite crystallographic structure plane is majorly due to the internal crystal arrangement and bonding.