Which element is represented by the letter X? 1.
silicon
2.
lead
3.
nitrogen
4.
hydrogen

Florian discovers a rock that is broken into pieces. each piece has several bands. which type of rock does florian predict these pieces will change into when subjected to heat and pressure? igneous magma metamorphic sedimentary

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Long term exposure to waves can cause sunburns and skin cancer.