Question

The main arena of various activities of a cell is
A. Mitochondrion
B. Cytoplasm
C. Nucleus
D. Plasma membrane

Answer 1

Cell is the basic structural and fundamental unit of life. All the living organisms present on the earth are made up of the cells therefore also called as building blocks of life. Some organisms are made up of single cells and some are made up of groups of so, on the basis of their cell numbers they are diving into two categories: Unicellular and Multicellular organisms.

Complete answer:
A cell is capable of performing all the vital activities required for the life-like metabolism of nutrients, generating energy, and replicating it in order to produce further generation. Multicellular organisms are specialized to perform different types of functions in collaboration with the neighboring cells. They perform all the activities by communicating with each other and corporate cells become tissues and then the group of tissues leads to the formation of organs which carry out the functions necessary for life.
The cell enclosed by the cell membrane, which performs as the selective barrier that allows nutrients to enter and waste product to eliminate. The cell is organized by different organelles; each organelle is surrounded by a separate membrane. The major cell organelle is the nucleus that contains the genetic material of the organism, also necessary for the growth and reproduction. Organelles also include mitochondria, lysosomes endoplasmic reticulum, Golgi apparatus. All the organelles perform a particular function as per the requirement of the cell. In addition, plants contain chlorophyll, which plays a major role in the process of photosynthesis. All these organelles are the space in the cytoplasm called the cytosol.
The main arena of various types of cellular activities is performed by the cytoplasm. Cytoplasm consists of a bulk of protoplasm excluding nucleus and vacuoles. Endoplasm is the inner part of cytoplasm and it is usually in perpetual motion called cyclosis or cytoplasmic streaming. Cytoplasm contains various types of cell organelles. Cell organelles are highly organized subcellular protoplasmic structures that have a different shape, chemical composition and perform different functions.
On the basis of the cellular structure the cell is divided into two main parts

Prokaryotic cells: They are single celled microorganisms; they are also called primitive cells. Prokaryotes mainly include Bacteria and Archaea. They consist of a single cell therefore they perform all the activities in the single cell.
Eukaryotic cells: These cells have a nucleus enclosed within the nuclear membrane and complex organism. Protozoa, fungi, plants, and animals all have eukaryotic cells.

The correct option is B, cytoplasm.

Note: The cell was first discovered by Robert Hooke in 1665, during the observation of a piece of bottle cork under a compound microscope. Later it was observed by Anton Van Leeuwenhoek. He observed cells under another compound microscope with higher magnification. He noticed the mobility of the cell. But after that, in 1883, Robert Brown, a Scottish botanist, provided the very first insights into the cell structure. And he was able to describe the nucleus present in the cells of orchids. Study of different types of cells is called Histology.