Which structural characteristic is found in both plant and animal cells?
a. mitochondria
b. chloroplast
c. lysosome
d. cell wall

The best answer is A.

Mitochondria are small organelles found floating  free in the cytoplasm of both animal and plant cells. They consist of two membranes, an outer and inner membrane which has numerous folds creating layered structures called cristae.Inside the mitochondria, there is found  fluid called the matrix

 Mitochondria are the powerhouse of cells. Many of the reactions in cellular respiration that take place in the cell occur in mitochondria and thus these organelles are key in the production of energy .

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