Answer:
1.a shadow is caused by an object blocking light so that it does not reach a surface. The area in shadow appears black because there is no light falling on it----it appears dark. In fact most shadows are not totally black because light usually bounces around the obstruction off other objects.
2.Shadow gives us the shape about the object and we can know the nature of that image by it's shadow. ... As shadow is complete with the all features of objects like it's shape, size and everything; This helps to know whether the shape of the object. Hence, Shadow tells us about the shape of the object.
3.The bird or an airplane flying high in the sky do not cast their shadow on the ground because they are at very high altitude due to which the ground which acts as screen for the shadow is far away and in absence of the screen the shadow cannot be formed.
Step-by-step explanation:
BY Roses_are_Rosie