Answer:
Most of the stars in our galaxy are made of hydrogen gas.
See that river on the bottom? That water has been flowing in the canyon for a long time and has slowly been chipping away at the rocks to give what you see today.
B. erosion from the water
Robert Hooke is the first person to observe cells as microscopic structures.
He was of British descent and, fun fact, he discovered cells by looking at a sliver of cork under a microscope lens (although the 'fun fact' is heavily simplified).
The bottom of the boat or the part that comes into contact with the water
