Idon’t get how to do it, could you me ?

Forests and meadows are often cut down to make way for farms or large number of new homes. what are some of the elements of ecosystems that are lost when plants in these areas are removed?

Calculate - analysis of compound composed of iron and oxygen yields 174.86 of fe and 75.14g of o. what is the empirical formula for this compound?

How many moles of gas are present if p=11 atm, v=12l, t=185k?