18
In chemistry, a group is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table; the f-block columns are not numbered.
Answer:
Ecosystem services are indispensable to the wellbeing of all people, everywhere in the world. They include provisioning, regulating, and cultural services that directly affect people, and supporting services needed to maintain the other services.
6.022 x 10^23, this is avogados number, a mole has 6.022 x 10^23 of anything, but in this instance, it is 6.022 x10^23 atoms of carbon.
It is more likely to be found as a COMPOUND, as it is more reactive, by the time we found them, they're already reacted with other elements or compounds to form new compounds.
Example is oxygen, it is very reactive, therefore we often found oxygen in water, which is H2O, in earth, instead of just pure oxygen.
