Aplants root system is which level of organization

Using a wheel and axle, a farmer is trying to lift a bucket of water from the bottom of a well. the larger wheel has a radius of 40 cm compared to the axle that has a radius of 10 cm. if a bucket of water is 50 n, then how much effort is required to raise it? 12.5 n 200 n 2 n 500 n

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

Explain why electric current cannot exist if a current doesn't have a voltage source.