Ahard, crystalline solid with a high melting point does not conduct electricity in any phase. this solid is most likely
(a) an ionic solid.
(b) a metallic solid.
(c) a molecular solid.
(d) a network covalent solid.

d. a network covalent solid.

Explanation:

A network covalent solid -

In these type of solids , the atoms are connected to each other via covalent bonds , its consists of large number of atoms connected in a three dimensional arrangement.

Hence, from the given information of the question,

The correct term from the given options is d. a network covalent solid.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

hope this : )