What's the independent variable, the dependent variable, the constant for my project "does nail polish affect the growth of nails" my materials are nail polish, ruler ,fingers

Ineed to find the answer of this question because i dont understand it

How many moles is 14.5 cm^3 of platinum? the density of platinum is 21.45 g/cm^3.

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?