Harold is worried that his young son has not yet developed an understanding of object permanence. What is one piece of information that he would most likely benefit from knowing?
a. Piaget's observations are absolute and based on the best science available.
b. Concepts identified by Piaget shouldn't be taken seriously whatsoever.
c. Piaget was careful in selecting children from a range of cultures to give his observations broad validity.
d. Piaget may have been mistaken about the relative age ranges that some children acquire certain skills

Astudent is performing an experiment comparing sound and light waves. the student gathers the following data. what conclusion does the student most likely make based on this data? light waves always travel the same speed; however, the speed of sound is determined by the medium that it travels through. all sound waves always have the same energy, so the temperature of the medium does not affect wave speed. light needs to vibrate particles, so it travels fastest in tightly packed solids, while sound does not need a medium, so it travels fastest in a gas. tightly packed particles in solids slow down the light waves; however, sound waves make particles bounce into each other, so they travel faster in solids.

The softest and hardest minerals are: softest hardest

The two required components for a generator are