Mechanical digestion so breaking down of the food in your mouth. Hope this help :)
A codon is a sequence of three nucleotides in DNA or RNA that codes for either a particular amino acid or tells the cellular machinery to start or stop using the code. It isn't located anywhere specific.
Each sieve tube element is normally associated with one or more nucleated companion cells, to which they are connected by plasnodesmata (channels between the cells). Each companion cell is derived from the same mother cell as its associated sieve tube member. Sieve tube members have no cell nucleus, ribosomes, or vacues. Thus, they depend on companion cells to provide proteins, ATP, and signalling molecules
