The answer is option C "Warm air rises as cooler, denser air falls." Convection is heat transfer between two objects for example a hot metal pot to a spoon. During convection hot air rises and cold air (or denser air) sinks.
Hope this helps.
Answer:
The meristem is a type of tissue found in plants. It consists of undifferentiated cells (meristematic cells) capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants.
Because the have hollow bones, feathers, wings, beaks, and they lay eggs