1) The process of photosynthesis, performed by plants, algae, and some bacteria, is responsible for producing the oxygen we breathe.

2) A newborn kangaroo is about 1 inch (2.5 centimeters) long and weighs less than a gram.

3) The total length of your blood vessels can circle the Earth more than twice.

4) The President of the United States serves as the head of state and the head of government, responsible for leading the executive branch and representing the nation domestically and internationally.