What pieces of evidence from the virtual lab could you use to support the following claim: Atoms from sugar molecules may combine with other elements via chemical reactions to form other large carbon-based molecules. (the virtual lab was just building glucose, fructose, and sucrose molecules)

Increase occurs in size and difference in chemical structure.

Explanation:

The first piece of evidence that is happen is the enlargement occurs in the size of the product molecule and the second piece of evidence is the difference in the structure of the both atoms of sugar molecule (glucose or fructose) and the large carbon based molecules which is formed. These two evidences are enough to verify the claim that when the sugar molecules combine with each other forming a new carbon based molecule which is larger in size.

the animal that would be cutest if scaled down to the size of a cat? elephant

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.