Which of the following is made up of dead cells?

Step-by-step solution

Collenchyma is living mechanical tissue. Phellem or cork is made up of dead cell and its cell wall is deposited with suberin which makes it impermeable. Sieve tube elements are long, tube-like structures, arranged longitudinally and are associated with the companion cells. Their end walls are perforated in a sieve-like manner to form the sieve plates. A mature sieve element possesses a peripheral cytoplasm and a large vacuole but lacks a nucleus. The functions of sieve tubes are controlled by the nucleus of compani