Explanation:
To swim, they move their tails up and down, rather than back and forth as fishes do. This is because whales evolved from walking land mammals whose backbones did not naturally bend side to side, but up and down. ... Whales do the same thing as they swim, showing their ancient terrestrial heritage.
Cetaceans are fully aquatic marine mammals belonging to the order Artiodactyla, and branched off from other artiodactyls around 50 mya (million years ago). Cetaceans are thought to have evolved during the Eocene or earlier, sharing a closest common ancestor with hippopotamuses.
The 'cheek' is the common name for the insect GENA.
The gena is located in the head area of insects. The gena forms the sclerotized area on each side of the head, below the compound eyes, which extends to the gular structure. The gena varies among species of insects.
External stimulus. The rain is something out of your control while you're waiting. Rain is not something you are doing nor is it a response to you waiting for the bus.
Answer:
Organ level– an organ is a structure composed of at least two different tissue types that perform a specific function within the body. Examples include the brain, stomach, and liver. Complex functions begin to emerge at this level.
Explanation: