Why does a plant cell have a cell wall and a cell membrene while the animal only a membrane?

How was the climate when the ambulocetus was alive

As the human population grows, what happens to our natural-resource requirements? o they increase o they decrease o they do not change. they go in cycles

It is believed that europa, one of jupiter’s moons has an ocean beneath its surface. based on how earth’s oceans and atmosphere are believed to have formed, what can be said about europa’s supposed ocean? the arrival of in the early days of europa’s existence could have formed its ocean. it is likely that the water experienced , similar to earth. it is also possible that this water is retained beneath europa’s surface and in its atmosphere due to europa’s .