What characteristic is unique to echinoderms?

All echinoderms bodies are divided into 5 parts. Starfish, for example, all have five arms and five sets of digestive and reproductive organs. If an arm breaks off, it will grow back.

from the original order (top to bottom) the new order will go

1 (founder)

4 (hawk)

2 (mutate)

3 (next generation)

the transfer for conduction is the heat transfering from the liquid to the spoon

the transfer for convection is the heat rising from the liquid to the air

the transfer for radiation is the heat going through the sides of the cup and to the air

at least that is what i would do