The arterial end is the part where the blood enters from the capillaries into the alveolus. The PO2 at the arterial end has a lower concentration of oxygen that is the PO2 is 40 and once this blood enters the alveolus the oxygen from the air in the alveoli dissolved in the blood hence increasing the PO2 of the air. The PO2 of the air remains the same until it reaches the body part where the oxygen is again consumed. Hence the option PO2 in the capillaries is lower than the PO2 in the alveoli is the right option
I think B Hope this helps you
Some ways in which communicable diseases spread are by: physical contact with an infected person, such as through touch (staphylococcus), sexual intercourse (gonorrhea, HIV), fecal/oral transmission (hepatitis A), or droplets (influenza, TB) travel through the air, such as tuberculosis or measles.
Answer:
Explanation:As previously stated, DNA is a macromolecule that's made up of individual subunits called nucleotides. Each nucleotide has three parts:
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A deoxyribose sugar.
A phosphate group.
A nitrogenous base.
DNA nucleotides can contain one of four nitrogenous bases. These bases are adenine (A), thymine (T), guanine (G) and cytosine (C).
These nucleotides come together to form long chains known as DNA strands. Two complementary DNA strands bond to each other in what looks like a ladder before winding into the double helix form.
The two strands are held together through hydrogen bonds that form between the nitrogenous bases. Adenine (A) forms bonds with thymine (T) while cytosine (C) forms bonds with guanine (G); A only ever pairs with T, and C only ever pairs with G.
Complementary Definition (Biology)
In biology, specifically in terms of genetics and DNA, complementary means that the polynucleotide strand paired with the second polynucleotide strand has a nitrogenous base sequence that is the reverse complement, or the pair, of the other strand.
