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.
Answer:
Air speed of bird is 
mph
Explanation:
let the speed of the bird in still air be "X"
Speed of the bird when it flies in the direction of flow of wind 
Speed of the bird when it flies in the opposite direction of flow of wind 
The total time taken is equal to 
minutes
hours
The distance in miles is equal to 
miles
On solving the above equation, we get -
Air speed of bird is mph
Answer:B
Chorionic Villus Sampling
Explanation:
This is a prenatal test which involves taking a chorionic sample from the Placenta for testing
Yes it is. Sometimes the geosphere is called the lithosphere. Hope this helps:)
