The nucleus is important to a living cell because <span> it serves the function of information storage, retrieval and duplication of genetic information. It is a double membrane‐bound organelle that harbours the genetic material in the form of chromatin.</span>
I think its the Diurnal Cycle.
A. endoskeleton
Endoskeleton is not a characteristic of Arthropods that has attributed to their diversity and success. Endoskeleton is defined as inner characteristics of the skeletal feature of an organisms such as bears, humans, fish and etc.
Exoskeleton on the other hand is the trait by which arthropods posses. It is skeletal feature that is described outside or is extrinsic, this is evident as crabs have their skeletons outside of their body.
8. eukaryotic cell
9. this organelle are structures that have specific jobs within cells
10.plants *I believe*
Answer:
The main difference between sieve tubes and companion cells is that sieve tubes are the long, narrow, pointed tubes present in the phloem of angiosperms whereas companion cells are attached to the sieve tubes, regulating the activity of sieve tubes.