Which phrases describe oxygen's roles in Earth’s atmosphere? Select three options. allows fuels to burn forms clouds that produce rain is the gas that animals breathe is used by plants to produce food forms ozone that absorbs the Sun's harmful rays

Explanation:

Oxygen is a powerful oxidizer (oxidizing agent or oxidant) that burns the fossil fuel, reacts with carbon, and produce CO2/CO. Although, it is not a sole oxidizer available on Earth but 99.9% of combustion reactions takes place in the presence of oxygen. It does the job by accepting electrons very fast in its valence shell.

Animals use oxygen to breath which produces ATPs through a series of chemical reactions particularly in electron transport chain. Again, it acts as a oxidizer and accepts electron in the electron transport chain. This gradient of electron flow is necessary for ATP production. In the end, water and CO2 are produced with ATPs.

Oxygen molecules in the stratosphere reacts with solar radiation (UV) and produce oxygen atoms. Thereon, each atom reacts further with the oxygen molecule to produce ozone. Ozone layer acts as a shield and doesn't allow penetration of harmful rays to the biosphere where living organisms are present.

rain is the best answer

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.