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.
<span>A scientific law describes repeated observations under a given set of conditions. These laws are not too specific, and they imply a casual relationship. These laws do not explain why something occurs, they merely state that something will occur if the given conditions are met. Therefore, the formation of a scientific law is a result of repeated observations. An example is Newton's first law of motion, which gives certain conditions for an object, such as no force acting on it, and then describes what the object will do in that situation, that is, remain in motion or remain stationary.</span>
The answer to your question would have to be C
Some foods and eating patterns may make it easier to keep obesity in check. Healthy food choices and diet patterns that help prevent heart disease, diabetes, and other chronic conditions may also help to prevent weight gain.
Eat whole foods-whole grains, vegetables, fruits, nuts, healthful sources of protein (fish, poultry, beans), and plant oils. Processed food should be minimal. Limit sugared beverages, refined grains, potatoes, red and processed meats, and other highly processed foods, such as fast food.
