Final answer:
Both the assertion that it is important for organisms to have cells and the reason that a cell maintains its chemical composition are correct, with the reason providing the correct explanation for the assertion, aligning with the principles of cell theory and homeostasis. The correct option is (A).
Step-by-step explanation:
Assertion: It is important that organisms have cells. Reason: A cell keeps its chemical composition steady within its boundary. The correct answer to this assertion and reason question is Option A: Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
Organisms are composed of cells, which are the basic units of life. This is a fundamental concept known as the cell theory, which states that all living things are made up of cells, and all cells come from pre-existing cells. Cells are not only foundational to the structure and function of all organisms but are also pivotal in maintaining homeostasis—the regulation of the internal environment to maintain a constant state, despite external changes. Cells are able to preserve homeostasis by controlling the flux or movement of materials in and out of the organism. This is done through various structures like cell membranes, cell walls, and specialized coatings in multicellular organisms.
Furthermore, all cells contain DNA that they pass on to daughter cells, ensuring the continuity of genetic information. The assertion underscores the importance of cells to organisms for creating and maintaining a distinct living system, while the reason explains how cells maintain a stable internal environment which is essential for life. Therefore, the reason is indeed the correct explanation for the assertion.