F. fluorite scratches limestone and gypsum G. Gypsum scratches talc
H. Limestone scratches talc
J. Calcite scratches gypsum

J. Calcite scratches gypsum.

Explanation:

Since limestone and calcite have about the same hardness, either limestone or calcite can be used in the hardness test to identify the softer gypsum.

explanation:

venn diagram is pictorial representation with of circles showing the relation between two finite sets or things. the intersection part of two circles conveys the relation present in between those sets or things.

here in the venn diagram of sand and salt two circles represent sand and salt. but the area falling under the intersection of these circle represents the mixture of sand and salt.

so, in a venn diagram the mixture will be placed in a middle that is in between the intersection of two circles.

b. accuracy of the data matters alot more than its number of digits, organization or amount of detail. quantitative observation is more accepted than the qualitative observation.