If an isotope of some element has a half of 300 years about how much of the isotope will be in sample after 300 years

A half-life is how long an isotope takes to break down. A 300 year half life means that half of the sample will be left after 300 years.

burning of wood and coal

explanation:

the panel also concluded there's a better than 95 percent probability that human-produced greenhouse gases such as carbon dioxide, methane and nitrous oxide have caused much of the observed increase in earth's temperatures over the past 50 years.

answer: blah

explanation:

bc blah