Which of these is a medium of transportation in plants?

Step 1: Analyze the question The question asks which option is a medium (a substance or fluid in which materials move) for transportation in plants.

Step 2: Explain the concept Plants move water, mineral salts, and food through the xylem and phloem. Within and between cells, substances dissolve and move in watery fluids. Cell sap is the liquid inside the vacuole of a plant cell. It is a solution of water, sugars, salts, and amino acids, and it serves as a medium for storing and moving dissolved substances. Phloem sap, a related fluid, carries manufactured food.

Step 3: Check each option

• A. Cell sap: A fluid solution that dissolved substances can move through, so it is a transport medium. ✔
• B. Nucleus: Controls cell activities and holds genetic material. It is not a transport medium. ✘
• C. Mitochondrion: Site of aerobic respiration, which releases energy. It does not transport materials. ✘
• D. Ribosome: Site of protein synthesis. ✘

Step 4: Answer Only cell sap is a fluid medium, while the others are organelles with other functions. The correct answer is A. cell sap.

Tip: When you see "medium of transport," look for a fluid, such as cell sap, blood, lymph, or water. Organelles like the nucleus, mitochondrion, and ribosome have specific jobs: control, energy, and protein synthesis. A quick way to remember: Nucleus = control, Mitochondrion = energy, Ribosome = protein.