I believe the answer is b.
The right option is; D Luster
If a mineral has a metallic shine to it, the luster of the mineral is being measured.
Luster is the property of a mineral which describes how the mineral reflects light, and also the dullness or brightness of the mineral. Luster is grouped into two which are; metallic and non-metallic. Minerals with a metallic luster are reflective and opaque. An example is pyrite. Non-metallic luster are also classified into groups based on how much light is reflected. The groups include pearly, dull, waxy, resinous, silky, and vitreous luster.
To solve the problem, let us note that the calcium percentage no longer considers the moisture content of the canned dog food. Taking the 75% of the sample 681 grams results in a moisture content of 510.75. This is "removed" from consideration and we're left with 170.25 grams which we multiply with the given (dry basis) percentage of calcium to get 2.043 grams of Calcium.
There are 4 bases:
Adenine,
Thymine,
Guanine,
Cytosine.
DNA replication begins when something called Helicase (an enzyme) unwinds the helix structure of the DNA. It does this so that Primase can then come along and set down an RNA primer.