Question

Assertion: Organisms are made up of cells.
Reason: Cells are structural units of living organisms. A cell keeps its chemical composition steady within its boundary.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Answer 1

The cell is a small structural unit of living beings capable of working independently. As in bacteria and protozoans, a single cell may be a completely mature organism itself. A cell is the structural and functional unit of all organisms that is capable of carrying out all life processes and acts as a building block of all organisms (both unicellular and multicellular).

Complete answer:
Various elements of plants and animals are made of cells. The smallest unit of life is a cell and can perform all living functions. The principal structural component of life is cells. And because of this the essential structural and functional elements of life are called cells. In their proportions, shapes, and the roles they perform, all cells are different. In reality, the cell's size and shape are related to the basic role it performs. A single-cellular organism often represents and digests food, breathes, excretes, develops, and reproduces. In multicellular organisms, the same functions are performed by groups of distinct cells grouped into tissues and organs, as in higher-level plants and animals. Thus, the essential structural and functional unit of life is called the cell.
All cells are delimited by a plasmalemma/cell membrane, a biological membrane that divides the interior of the cell from the surrounding and other cells. The cell membrane, being a selectively permeable layer, only allows the exchange of desired molecules to preserve the specific chemical composition of the interior of the cell.
Thus, choice A is the correct one.

Note: As the essential constituent of life, cells are taken into account since they come in distinct and easily distinguishable packets. Cells are surrounded by a structure known as the cell membrane, which serves as an outline between the internal and external structure of the cell, much like the walls of a building. It is also called the plasma membrane of this cell membrane.