Carbonic acid releases H3O+ ions into water in two stages. a. Write equations representing each stage.

(Please do not answer if you don’t know what you’re talking about.)

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

Harry lives in a city, and he has a lung condition known as asthma. on certain days, harry has to stay inside because pollutants in the air make it difficult for him to breathe. which of these pollution sources are nonpoint sources that might bother harry if he goes outside? choose the two that apply.

Individuals within populations exhibit some diversity. as a result of possessing slightly different traits, some individuals are better able to survive and reproduce than others. if these individuals changes in the characteristics of the population may occur over time. the cumulative change in these characteristics is known as