What indicates a river valley on a topographic map and how do you know the direction the river is flowing?
I NEED AN ANSWER FAST!!

A blue line indicates that there is water running through the valley. If there is not a blue line the V pattern indicates which way water flows.

answer: the correct option is d. enzyme

lactase and carbonic anhydrase are the examples of enzymes.

lactase is an enzyme, which is present in the small intestine of mammals. it in the digestion of the disaccharide, lactose ( milk sugar) by converting it into two monosachharide, which are glucose and galactose.

carbonic anhydrase is present in the red blood cells. this enzyme plays significant role in the transport of co₂. it in the conversion of co₂ and h₂o into carbonic acid, which is then dissociated into bicarbonate ions and hydrogen ions.