The correct option is A.
Puppies normally growl when playing; this type of growling is not aggressive. The growling that are made in such situations indicate the pleasure of the puppies as they are playing together, such growl does not result in biting or any other injuries.
Answer:
The hydrosphere refers to the water on the earth crust. If there were no hydrosphere, we would not have lakes, oceans, rivers, or even a hose full of water.
The stomata of leaves are surrounded by guard cells. The guard cells help the leaves to regulate the rate of transpiration of water from the leaves by opening and closing the stomata. When water enter the guard cells, they swell and bulge and this makes the stomata to open. So, with high water pressure, the guard cells will stimulate the stomata to open. The reverse will be the case if the water pressure is low.