If a wave hits a smooth surface at an angle of incidence of 40 degrees, the angle of reflection is
a. 40 degrees.
b. 0 degrees.
c. 80 degrees.
d. 90 degrees.

the earths atmosphere is made up of nitrogen and oxygen. solids can turn into gasses through a process called sublimation. sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase.

hope this : d

according to jean piaget, in what stage of cognitive development are children able to understand conservation task?

b. preoperational

just took it