2. Which of the following nucleotide bases are BOTH pyrimidines?
A. cytosine and adenine
B. cytosine and guanine
C. thymine and guanine
D. uracil and adenine
E. cytosine and uracil

E. cytosine and uracil  

Explanation:

Pyrimidine is an aromatic compound similar to pyridine. The difference is that it has two nitrogen atoms at positions 1 and 3 in the ring.

The pyrimidine bases have the same six-membered ring structure with two N atoms at the 1,3-positions.

In addition, cytosine has a carbonyl and an amino group, while uracil has two carbonyl groups.

the major parts of the digestive system:

salivary glands.

pharynx.

esophagus.

stomach.

small intestine.

large intestine.

rectum.

accessory digestive organs: liver, gallbladder, pancreas.

hypoxemia refers to a below usual concentration of oxygen in the blood, mainly in the arteries. hypoxemia is an indication of an issue associated with circulation or breathing and may lead to various symptoms like shortness of breath.  

the condition is identified by determining the level of oxygen in the blood sample obtained from an artery. it can also be predicted by determining the oxygen saturation of the blood with the application of a pulse oximeter.  

the normal arterial oxygen is about 75 to 100 mm hg. the values underneath 60 mm hg is generally considered with the requirement for supplemental oxygen. the normal pulse oximeter readings generally range between 95 to 100 percent. the values under 90 percent are regarded as low.  

in the given case, the oxygen saturation is measured at 93 percent, hence, there is no need to administer oxygen, that is, one should withhold oxygen.