Which pair represents isotopes?

a. All of the other answers are correct
b. Oxygen-16 and oxygen-18
c. Uranium-235 and uranium-238
d. 238U and 235U
e. A carbon atom with 6 neutrons and a carbon atom with 8 neutrons

A. All of the other answers are correct

Explanation:

Each pairs are from the same elements, meaning they share the same atomic number but different nucleon number (neutron number + atomic number). Thus, all of the answers are correct.

is there multiple choice answers?

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.