Copernicus's model states that the sun is in the center, and that the planets move around it in a circle. Kepler's first law of planetary motion says that they move around the sun in an ellipse.
A lighted candle produces heat however not as much heat as a heater or the sun would.
Answer:
During stage 3 - late expanding (of demogrpahic transition model)
Explanation:
During stage 3, birth rate begins to decline as infant mortality is lower and women have more access to education, family planning, and contraceptives. Children are not needed as "free labor" as they might have been in earlier stages.
Answer:
Explanation:
Given
altitude of the Plane 
When Airplane is
away
Distance is changing at the rate of 
From diagram we can write as

differentiate above equation w.r.t time

as altitude is not changing therefore 

at 
substitute the value we get 
