Steel has a small amount of carbon atoms place in the little spaces that exist in between iron atoms. This means it can be classified as a alloy.​

Alpha particles have positive charge, beta particles have negative charge, and answer 4 just doesn’t make sense. thus, you are left with only one possible answer.

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab. 

The molar mass of a substance is defined as the mass of 1 mol of that substance, expressed in grams per mole, and is equal to the mass of 6.022 × 10 23 atoms, molecules, or formula units of that substance.