the answer is concave lens
Engineers have designed experimental cars that use liquid hydrogen for fuel instead of gasoline. this is an example of Substitution.
Substitution is the process where one thing replaces other for a particular purpose. here liquid hydrogen is replacing the gasoline for fuel in car. hence the correct word to fill is Substitution.
The formula for speed is:
Speed = Distance/Time
We can plug in the given values into the above equation:
Speed = 570m÷24s
Speed = 23.75, which rounds to 24m/s as a whole number. Therefore, the answer is b.
First , ocean currents are actually big convection currents moving heat around. Second, ocean currents moves food and nutrients from deeper water in a process called upwelling.