Describe how cell membranes are selectively permeable

How many teeth does an average human have

Roger sees water balloons fall past his window. He notices that each balloon strikes the sidewalk 1.2s after passing his window. Roger's room is on the fifth floor, 25m above the sidewalk.

List the number of atoms for each element in this compound: / (NH_{3} / )

What did Edwin Hubble discover about galaxies that allowed him to determine the expansion rate of the universe? A. The farther away a galaxy was, the less its light was shifted toward the red end of the spectrum. B.

At a maximum level of loudness, the power output of a 75-piece orchestra radiated as the sound is 70.0 W. What is the intensity of these sound waves to a listener who is sitting 25.0 m from the orchestra?

2x^2:3=dg solve for x

A 2.25-kg block is released from rest on a ramp of height h. when the block is released, it slides without friction to the bottom of the ramp, and then continues across a surface that is frictionless except for a rough patch of width 15.

Which of the following are steps for balancing chemical equations? Check all that apply. ] A. Multiply the reactants to get the products. B. Change subscripts. O C.

1. Why does the water vapour in clouds condense? 2. Explain why you can see clouds but not see the water vapour in the air

What are some similarities between electricity and gravity?