The right answer is C. I think, a. and d. are obviously not serious. B is not true, because Ag and Au are in the same group in the periodic table and therefore have the same number of electrons in the last level. So, they form ions with the same charge. C is true beacause Ag and Au have different numbers in the periodic table and different amount of protons and neutrons in their nucleuses.
It can breakout if the resistance stayed the same
When cell over divide they cause a sickness or cancer
Answer:
Companion cell is a type of specialized parenchyma cell, which is located in the phloem of the flowering plants.
Each of the companion cell is usually associated with the sieve element. The main function of the companion cell is uncertain but it regulates the activity of sieve tube.
It plays a major role in the loading and unloading of the sugar molecules into the sieve element. As the sieve tubes do not have nucleus and ribosomes so they need companion cell to help in the transportation of sugar molecules.