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 never form inside a nebula but a nebula can be produced by any star.
B.
Stars can form inside a nebula but a nebula can never be produced by any star.
C.
A star always has a higher density than a nebula.
D.
A nebula always has a higher density than a star.
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pla·gia·rism

/ˈplājəˌrizəm/

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noun

the practice of taking someone else's work or ideas and passing them off as one's own.

explanation:

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.