Complete the following sentences by writing in the correct word. In a neutral atom, the number of electrons must be the same as the number of
.
The subatomic particle in an atom with no charge is the
.
The number of protons in an atom is the
number.
The total number of protons and neutrons in an atom is the
number.

What does the process of natural selection involve

What are the similarities of physical and chemical change ?

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.