A simplified model of protein synthesis is shown here: How might this model be revised to show a more accurate depiction of protein
synthesis?
Prior to process 1, DNA should copy itself to allow the cell to divide
After process 2, the completed protein should travel back to the nucleus
Between processes 1 and 2, the mRNA must be modified before leaving the
nucleus
During process 2, the ribosome should remove any mutated nucleotides
from the mRNA

The correct options are:

Prior to process 1, DNA should copy itself to allow the cell to divide.

Between processes 1 and 2, the mRNA must be modified before leaving the  nucleus.

Explanation:

For eukaryotes, the mRNA is made in the nucleus from the DNA. This process in known as transcription. The process of making proteins from the mRNA takes place in the ribososmes of the cytoplasm. This process is known as translation. The mRNA has to be modified before it is transported for translation. Otherwise, the mRNA will be degraded by the enzymes of the nucleus.

sulfur dioxide

explanation: acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. these substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.