Sand this is because It takes thousands of years for a rock to turn into sand
Answer:
Option-C
Explanation:
A pulse-chase experiment which is used to study the cellular process taking place in the cells. This uses the labelled molecule which is incorporated into the cellular pathway and then the unlabeled molecules are used over time to determine how much time is required by the unlabeled molecule to replace the labelled molecule.
In the given question, the pancreatic cell which secretes the digestive enzyme known as the acinar cell is labelled with the leucine and then used unlabeled leucine.
When observed after three hours, the black spots will appear on the exterior of the cell as the protein has been synthesised by the ER and now has been secreted from the cell.
Thus, Option-C is the correct answer.
Answer:
it is the change in one or more genes
The valves are responsible for preventing blood from flowing in the wrong direction, they are present in the veins, and the arteries don't need them because the aorta (biggest artery) pumps or in other words pushes it with such a force that no other force can change its direction, in the veins there is no structure present for pumping them as a result we have got valves so that they go in one direction...... the meaning of the word valve is to allow in one direction