What is the difference between the speed of an object, the velocity of an object and the acceleration of an object?

Speed is the rate of change of distance(basically how much distance(m) has been covered in a particular time(s)). Velocity is the rate of change of displacement( change of distance in a particular direction with respect to time) , and acceleration is the rate of change of velocity per unit of time.

the leaf is an organ of a typical plant, and the main functions are to complete photosynthesis and allow the plant to exchange gas, just like how we have the respiratory system. leaves have the stomata, which collects maintains co2 and o2 levels. this is necessary for cell metabolism. the leaf also collects sunlight using chloroplasts. succinctly, leaves own a pivotal role in sustaining plant life.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.