music: 60's Chart Toppers: Name The Artist: The Majestic?

Questions

Acute febrile virus disease of tropical Africa?

Member of French Light Infantry corps originally formed of Algerians and retaining their oriental uniform?

In chess an obligation to move even when that move is disadvantageous?

Parallel lines made to appear not parallel by short oblique intersecting lines?

The splitting of spectrum line into several components by magnetic field?