So sorry , i will give whoever does all of these brainlist . :)

1. constant speed is a steady speed from start to finish, instantaneous is not constant from start to finish.

2. The average speed of the marble is 5 m/s  (meters per second).

3. Rider 1 will arrive at the destination before Rider 2.

Hope This Helps!  : )

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

here's your answer.