Which of the following statements is true?

kinetic energy depends on mass, gravity, and speed.
all machines lose some energy because of friction.
heat lost during work is easily recovered and used for useful actions.
temperature and heat are the same.

Jessica is traveling from miami, florida, to chicago, illinois. using the map, tell one way the land will change during the second half of her trip.

In numbering carbon atoms in the parent chain of a hydrocarbon, why would you number from right to left, rather than left to right

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.