Question

how did the boy hear about the river​

Answer 1

Answer:

can you ask the question in detail?

Explanation:

it's hard to understand the question

Answer 2

Answer:

Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.

#JUST_SpAmmIng