One of the 4 nucleic acids that make up dna. It is purine derived & pairs with thymine.
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<h3>1. Hepatitis B </h3><h3>2. Levels of circulating antibodies against a certain antigen.</h3>
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Cells are so little, so they can maximize their ratio of surface area to volume.
Explanation:
Smaller cells have a higher ratio which allows more molecules and ions to move across the cell membrane per unit of cytoplasmic volume. Cells are so small because they need to be able to get the nutrients in and the waste out quickly.
It is a cold Artic air mass over Siberia. Air masses are altered because it doesn't stay in one place and changes as it moves due to the temperature of environment that can be caused by moisture. The cold Artic Mass from Siberia will go to the North Pole, Canada then moves further to the South area.
