In fetal life, the lungs are not expanded, so most of the blood from the right ventricle is shunted from the pulmonary artery to the aorta through the patent ductus arteriosus. With a few breaths the lungs expand, and blood flows from right ventricle to pulmonary artery into the lungs. Withdrawal of circulating prostaglandin from the mother plus bradykinins released from the expanding lung of the infant cause the ductus to close over a few minutes to hours. The closed ductus remains as the ligamentum arteriosum.
B) The Earth's crust is pulled apart creating deep folds and then pushed together generating steep scarps to create fault-block mountains
The answer is false, liquid molecules continue to move even after the concentration is uniform.
Diffusion happens because there’s a concentration gradient between the dye and the water, therefore dye molecules moves to the water area. But note that this is only the net movement of the molecules, which means, even if more molecules are moving towards water, there are still some dye molecules that are moving in the opposite direction.
So, after the concentration is equal, the motion of the dye molecules does not stop, they still move in random directions, but there’s no net movement instead, as there’s no concentration gradient. Remember molecules are always moving in all directions , it just depends on whether there’s a net movement or not. If there’s no net movement, the amount of molecules moving to each and every direction is always equal.
Hormones -- such as melatonin and cortisol; the former signals the body to go to bed, while the latter signals for the sleeping person to wake up -- are created by physiological changes.
