The purpose of the immune system is to identify and eliminate foreign substances within the body. in which of the following cases is an immune response not beneficial?
i. allergic reaction
ii. bacterial infection
iii. organ transplant
iv. viral infection

How can you keep track of variables in a science experiment?

Witch type of microscope is used to view very small cell components like proteins and dna?

Which set of characteristics best describes sedimentary rock? a) largest type of rock, made of organic matter, hardest type of rock b) often contains layers, forms near sources of water, contains fossils c) least abundant type of rock, made of other rocks, made mostly of minerals d) most abundant type in earth's crust, made of magma/lava, contains no fossils