Final answer:
Intercellular material is the option that is not a subcellular structure since it is found outside and between individual cells. The correct answer is option 1).
Step-by-step explanation:
The question at hand is which of the following is not a subcellular structure. The options given are intercellular material, membranes, cytoplasm, and organelles. Among these, membranes, cytoplasm, and organelles are all components of a cell that actually exist within individual cells, and therefore can be classified as subcellular structures.
Membranes, such as the plasma membrane, enclose cells and organelles, maintaining cellular integrity. The cytoplasm is a term referring to all cellular material inside the plasma membrane, excluding the nucleus, and contains substances like the cytosol and ribosomes.
Organelles are specialized subunits within a cell that have specific functions, such as mitochondria for energy production and the endoplasmic reticulum for protein synthesis. On the contrary, intercellular material is found outside and between individual cells, not within them, and thus is not a subcellular structure.