If two atoms combine by sharing electrons, what kind of bond is formed?

What is the polyatamic ion of thiosulfate

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.