Molds, casts, coprolites, and petrified wood are all example of

Molds, casts, coprolites, and petrified wood are all examples of fossils.

Explanation:

Molds are fossils formed by the authigenic preservation of an organism- it is covered gradually in mud or silt which hardens into rock leaving indents there after it has decayed. Similarly, casts are mineral deposit filled casts, which produce fossilized copies of the organism. Coprolites, fossilized fecal matter, are a type of trace fossil, which provides records the presence, diet and other habits of the organism in an area by its preserved excrement. Petrified wood,like molds and casts are mineralized, however the differs from molds as it has not undergone decay.

it's diluted or concentrated

in a diluted solution, you can add a lot more solute but in concentrated only a little more can be added