The first three are the same as those found in DNA, but in RNA thymine is replaced by uracil as the base complementary to adenine. This base is also a pyrimidine and is very similar to thymine. Uracil is energetically less expensive to produce than thymine, which may account for its use in RNA.
<h3><u>Answer;</u></h3>
A. Gas exchanges takes place by diffusion.
B. It is an open system.
<h3><u>Explanation</u>;</h3>
- Most molluscs and arthropods have an open type of circulatory system.
- Open circulatory systems pump blood into a hemocoel with the blood diffusing back to the circulatory system between cells.
- Blood is pumped by a heart into the body cavities, where tissues are surrounded by the blood.
The small intestine is the longest part of alimentary canal with a length of 4.5 to 7 m and narrow in width, while the large intestine is the hinder-most part of the alimentary canal with a length of 1.5 m. it called the large intestine because it has a width of 4-6 cm. Also in the large intestine circular folds are absent while its present in the small intestine.
As far as I know of B would be the correct answer but i am not positive
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