H2 + O2 → H2O

Why does his teacher ask him to balance the equation by including the correct coefficients?

A. to show that most molecules exist in pairs

b. to show that most compounds exist in pairs

c. to show that atoms are conserved in chemical reactions

d. to show that atoms are created in chemical reactions

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

What is a sex-linked genetic disorder that disrupts the blood's ability to clot? a.achondroplasia b.huntington's disease c.hemophilia d.albinism

How did alexander fleming’s research solve a societal problem? he developed ways to treat inherited diseases. he advocated for regular hand washing to kill germs. he discovered a new type of medicine that could treat infections. he discovered the cause of mad cow disease, an emerging disease.