The activation energy of an endothermic reaction
1. must be greater than the required δh
2.must be less than the required δh
3.must be equal to the required δh
4.is not needed for the required δh

What three things determine the shape and size of a puddle when water is poured out onto a surface

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.

How is the shape of the poem “peer” connected to its meaning?