A theory by which prokaryotes gave rise to the first eukaryotic cells. Chloroplasts in plants and mitochondrion in other eukaryotes are believed to have once been prokaryotic organisms engulfed by larger prokaryotic cells.

lunar landing mission. apollo 11 was the first manned mission to land on the moon. the first steps by humans on another planetary body were taken by neil armstrong and buzz aldrin on july 20, 1969. the astronauts also returned to earth the first samples from another planetary body.

explanation:

a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.