How to find the protons, nuetrons, and electrons of a isotope?

The footprints of a dinosaur and the burrow of an ancient shrimp are examples of which kind of fossils

Some molecular compounds, such as hcl, ionize completely in solution. for molecular compounds such as h2co3, most molecules do not ionize in solution. which describes the properties of these two solutes? a. hcl and h2co3 have the same effect on the properties of the solution. b. hcl raises the freezing point of water more than h2co3 does. c. hcl raises the boiling point of water more than h2co3 does.

In the diagram here that represents the reaction, which reactant, a or b, is the limiting reagent?