What is the structure labeled with an arrow?

a) cytoplasm

b) nucleus

c) cell wall

d) flagellum

The correct option is B. Nucleus

Explanation:

The structure in the diagram is a nucleus because the nucleus is a membrane-bound organelle mostly round in shape and it is present inside the cells.

The structure in the diagram cannot be cytoplasm as cytoplasm is a fluid in which organelles float.

The structure in the diagram cannot be a cell wall as a cell wall is the outer layer of a cell and it is not present inside of the cell.

The structure cannot be a flagellum as flagellum are hair-like structures. Hence, option A, C and D are false.

the organisms are not adapted to live in some communities or habitats.

prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.