Even though you are getting closer to the sun as you ascend into the troposphere, why does the temperature drop? the lower atmosphere is heated by the ground
warm air stays below cold air
the troposphere is a stable layer
ozone blocks the sunlight

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.

Draw two cyclic constitutional isomers of cis-1

Consider the story you just read. all but one of the choices below indicate that something is living.