Name any two items which can be easily recycled but are generally thrown in the dustbins by us.

The atomic numbers of three elements X, Y and Z are 3, 11 and17 respectively. State which elements will show same chemical properties.

Why is DNA copying necessary during reproduction?

List two advantages of growing grapes or banana plants through vegetative propagation.

"A convex lens of focal length 'F' can forma magnified erect as well as inverted image." Justify this statement stating the position of the object with respect to the lens in each case for obtaining these images.