Which type of heat transfer has warm fluids rising and cold fluids sinking?(science)

heat transfer in a fluid in which hot fluid rises and cold fluid sinks; setting up a cycle

the way that the mass of carbon can be conserved through cellular respiration is through a process/law called the law of conservation of mass which even tho it undergoes a process, mass is not be destroyed or changed

thymine. in rna, thymine is replace by uracil