A. maintenance of axons is not a cellular activity associated with microtubules.
Explanation:
Microtubules are hollow, bead-like, tiny tubular structure that helps cells maintain its shapes. Together with microfilaments and intermediate filaments, they form part of the cell's cytoskeleton. Microtubules also contributes to the cell movement or cytokinesis that includes muscle contractions in muscle cells. Microtubules also replicated chromosomes to opposite ends of a cell during cell division. Microtubules also contribute to the parts of the cell that help it move and are structural elements of cilia, centrioles and flagella. A bundle of microtubules makes up an axonemal structure of cilia and flagella.
Plants are autotrophs because they can prepare their own food. Photosynthesis takes place in leaves. Leaves contain stomata that allow for the exchange of gases during the process, and also help with the process of transpiration.