1) The first commercially available digital camera, the Dycam Model 1, was introduced in 1990 and had a resolution of 376 x 240 pixels.

2) In African mythology, there is a rich tapestry of diverse beliefs and stories across the continent's many regions and cultures. It includes deities, spirits, and mythical creatures, with narratives often addressing themes of creation, ancestral heritage, and the forces of nature.

3) The concept of separation of powers, as articulated by French philosopher Montesquieu, refers to the division of government responsibilities into distinct branches, such as the executive, legislative, and judicial, to prevent concentration of power.

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.