What makes a testable hypothesis?

a. it must ask a scientific question.
b. it must be predictable.
c. it must be able to be proved right or wrong.
d. it must follow the scientific method.

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.

The arrangement of particles is most ordered in a sample of

How many grams of phosphorus are contained in 5.09 moles of phosphorus?