<span>B. the He nucleus C.the He electrons D.the He quarks</span>
Answer/Explanation:
A theory has lots of scientific evidence to back it up. We know this to be true based on lots of different diseases and studies of their spread.
A hypothesis is more of a starting point - an educated guess based on limited evidence. It requires further testing before becoming a theory.
A law is something that can be generalized to lots of contexts, and is universal. Such as the law of thermodynamics.
B. since Phosphorus has an atomic mass of 30.974 (larger) than Magnesium which is 24.305 (smaller)
I'm assuming that you meant 55 g/cm^
3. Density=

. This is the definition of density. If you rearrange this equation by multiplying each side of the equation by the volume, you get: (Density)(Volume)=Mass. Divide each side by the density to get: Volume=Mass/Density. Now just plug everything in:
V=220 (grams)/55 (grams/cm^3)=<u>4 cm^3</u>