Answer:
I think so this is the answer
Answer:
answer b is the correct of this question
Answer:
<u><em>DNA is made of repeating units called nucleotides.</em></u>
Explanation:
DNA can be described as a double helix molecule made up of long polymer chains of nucleotides. The nucleotides which are present in a DNA are:
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)
The hydrogen bonds which occur in the pairing of nucleotides makes the double helix structure of DNA.
Adenine forms hydrogen bonds with Thymine.
Guanine forms hydrogen bonds with Cytosine.
The backbone of the DNA is made up of sugars and phosphates
Answer;
-Atrial contraction;
Explanation:
-The cardiac cycle comprises all of the physiological events associated with a single heartbeat, including electrical events, mechanical events (pressures and volumes), and heart sounds.The atria and ventricles alternately contract in each cardiac cycle. The pressures in the chambers change greatly over the course of the cardiac cycle.
-During atrial contraction, blood flows from atria (high pressure) to ventricles (low pressure). Similarly, this same pressure gradient exists during ventricular filling.
