A molecule that is important for cell functioning cannot diffuse through the plasma membrane, but needs a protein that can open and close to allow the molecule to diffuse. What is this protein called?

Describe the response the kidneys have to dehydration and excessive water intake. what happens to the concentration of urine in each case ?

Scenario #2 in 2001, a population of 2,500 poison dart frogs lived in the amazon rain forest. due to increased deforestation, the population dwindled to 25 frogs in 2019. new government regulations were enacted in 2022, successfully putting an end to the deforestation of the amazon rain forest. once deforestation was stopped, the poison dart frog population was able to recover. by 2050, the population reached 8,000 frogs, of that population, 20 are homozygous recessive for being spotted (ss genotype). q2- ? q- p- p2- 2pq-

Sally and sue were investigating the topic of friction in science. they used a small car and a ramp as seen in the picture to test what they were learning. they knew that they slipped easily on waxed floors but not on carpet, so they decided to change the material on the surface of the ramp to see what happened. they planned to use glass, carpet, aluminum foil, and sandpaper and run the car down the ramp over each surface. what would be the best research question to guide the girls' experiment? a) does the amount of surface area affect the friction on the moving car? b) will the car travel fastest on the glass surface? c) how does the angle of the ramp affect the speed of the car? d)do rougher surfaces tend to create more friction than smooth surfaces?