Two people must have the same speed and velocity if

They are jogging side by side at 5 m/s

Let's distinguish between the concepts of speed and velocity:

The first condition we have here is the fact that two people have the same speed, this means they are moving at the same rate of change of distance. The second condition must be met as well, if we wish them to have the same velocity, this means they should be moving in the same direction, let's say, along the positive or negative x-axis, but not in opposite directions.

- decrease the number of plants and animals living in the water.