32p can be used to make any nucleotide (a, c, g, or t) radioactive. which of the following explains why this is true?

a. all nitrogenous bases have a phosphorus atom that can be replaced with 32p.
b. all nucleotides have a phosphorus atom that can be replaced with 32p.
c. all sugar molecules have a phosphorus atom that can be replaced with 32p.
d. all isotopes of phosphorus have 15 protons and are unstable.

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.