Iron and lead are both metals, but iron is much harder than lead. How do you think Democritus might have explained this difference? btw its science

Tin has ten stable isotopes. the heaviest, 124sn, makes up 5.80% of naturally occuring tin atoms. how many atoms of 124sn are present in 82.0 g of naturally occurring tin? what is the total mass of the 124sn atoms in this sample?

What does the xylem do? stores the glucose captures the sunlight absorbs oxygen into the leaf carries water from the roots to the leaves

Δu of , in kj/kg, as it isto k, (a)as a of , (b) at , (c) at .