How old was this tree when it was cut?

around 19-20 years

it's hard to see and count all the rings.

Explanation:

First answer is covalent bonding

Second answer is 4 bonds. Because carbon has 4 electrons in its outermost shell

Lastly Yes, This allows them to form strong covalent bonds with a number of elements. Carbon can also bond with itself, allowing it to form long chains or rings of carbon atoms