At what age do pupils take their GCSE exams​

Ben is interested in using a source that provides original research, current and developing trends and experts within specific fields. which source should he use?

Earth's atmosphere is unique among the planets and is able to support life because it contains a large amount of a) oxygen b) helium c) methane d) carbon dioxide

Afarmer began a new method of reducing grain spills. this reduced the number of mice on the farm. the number of snakes in the surrounding area decreased at the same time. the snakes depended on the mice that lived in the field. what’s the likely reason the snake population decreased? a. the number of snake predators increased. b. the number of mice increased. c. the number of mice decreased. d. the pesticides affected the snakes. e. a new breed of mice moved into the field.