a person who participates in activities that are designed to change something in society a campaigner a formal meeting between leaders from two or more countries a summit to be expected or planned to happen at a particular time to be due to a place or organisation that provides the space for a special event a host someone who studies plants, animals, rocks, etc. a natural historian someone who publicly supports something and speaks in favour of it an advocate quantities of carbon dioxide that are sent out into the air and that are harmful for the environment CO2 emissions the process of changing to suit different conditions adaptation https://339efcb25eb75e967b0d-ff8eeadd950d51fd1fc939dca75b3973.ssl.cf1.rackcdn.com/assets_default.swf