The earth has always had oxygen in the atmosphere.

a) true
b) false

Is this mrna or rna need need the answer in a hurry

Which of the following is not a type of epithelial cell

Select the correct answer from each drop-down menu the images show fossils of a modern bird and two extinct organisms (a tyrannosaurus rex and an archaeopteryx). based on the structure of the three organisms, it can be concluded that the archaeopteryx and bird have wings, while dinosaurs have limhe se it can be concluded that