What was the major contributor of oxygen to earth's early atmosphere?

In the proto-solar system nebula, gravity pulled matter together to form larger bodies. As they collided, what happened to these bodies?

If a cell normally has 20 chromosomes how many chromosomes will each daughter cell have after it goes through mitosis

In transduction, the viral transfers dna from bacterium to bacterium Dna is moved through a tube between the cells. True / False.

Which scientist became famous for telling the world about environmental harm cause by ddt

Many cultures and religions have customs which deal with the way they use the land. For example, in Judaism, it is required that a field be left fallow (unplanted) every seventh year.

Which is a secondary disturbance? O A. Forest fire B. Volcanic eruption O C. Snow melting O D. Tree falling

What type of symmetry do sponges have? A. Radial B. Bilateral C. None

The synthesis of glucose by photosynthesis requires energy in the form of excited electrons. the source of the energy to excite the electrons is

What are the two components of a 5-methyluridine?

What term means that an antimicrobial drug can injure/kill the target cell or organism without injuring the person receiving the drug?