DNA is made up of deoxyribose sugar while mRNa is made up of ribose sugar. DNA has thymine as one of the two pyrimidines while mRNA has uracil as its pyrimidines base. DNA is present in the nucleus while mRNA diffuses into the cytoplasm after synthesis. DNA is double stranded while mRNA is single stranded.
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Answer:
Salivary glands secrete salivary amylase, an enzyme that begins the breakdown of starch into glucose. Mucus moistens food and lubricates the esophagus. Bicarbonate ions in saliva neutralize the acids in foods
The right answer is The first image (the left one).
An atrium is an upper cavity of the heart, delimited by a thin wall, receiving blood from the bloodstream. There are two in the human heart, they allow the passage of blood from the veins (cellars and lungs) to the ventricles (right and left).
In its upper part (near the entrance of the superior vena cava) is located the sinus node, microscopic structure from which the electrical impulse which ensures the contraction of the heart (especially atrium) ...
The depolarization of the action potential is conducted step by step in the cells of the right and left atria, accompanied by a contraction of the muscle fibers.
