Comprehensive detail and links between structure and functions of cells and different tissue (For animal Biology) (about a page long please)

In dna, only the_ varies from one nucleotide to another. base phosphate sugar amino acid

What was the land like over 500 million years ago? what was under the sea?

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 .