Which is a tough and rigid layer that surrounds plant cells, as well as some algal bacterial cells

The cell wall

Explanation: A cell wall is a rigid structure that surrounds a plant cell. A cell wall is made up of cellulose and thus is usually referred to as a cellulose cell wall . It gives strength and support to the cell and gives it a definite shape.

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

this is math not biology xd