The number of species on Earth tagged at 8.7 million as of 2011.
The main responsible for the delay among the atrial and
ventricular contractions is the action potential conduction velocity of the AV
node cells. If the atria and ventricles contract simultaneously, atria cannot
give any help in filling the ventricles, which is needed, especially in those
with stiff ventricles as in the elderly. Hence atria have to contract first and
then the ventricles.
Answer: Option D
Explanation:
Tuberculosis is usually treated by the end of six months or early. This is done by the first line TB drugs.
This disease is resistant to many of the antibiotics which is used by in case of Tuberculosis. These drugs were initially used to treat tuberculosis.
There are chances that this disease is not cured completely and is repeated again and again if the patient is not handled carefully.
The illness is very risky as it leads to coughing along with the blood clots and many more symptoms.