astronaut: Someone trained to travel into space for research and exploration.
bacteria: (singular: bacterium) Single-celled organisms. These dwell nearly everywhere on Earth, from the bottom of the sea to inside other living organisms…

astronaut: Someone trained to travel into space for research and exploration.
bacteria: (singular: bacterium) Single-celled organisms. These dwell nearly everywhere on Earth, from the bottom of the sea to inside other living organisms…