Question

do sieve cells arrise from pre-existing cells​

Answer 1

☞RBCs and sieve tube cells lack nuclei so, cannot divide and form new cells (new cells are not formed from pre-existing cells) Some protozoans and thallophytes (e.g. Acetabularia) have a body but are said to be acellular (body is not made of multiple cells)

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Answer 2

Answer:

It cannot divide and form new cells (are not formed from pre existing cells).