Final answer:
Actin filaments are found in the cell's cytoplasm and are involved in supporting the cell's structure and movement, whereas microtubules, also in the cytoplasm, maintain the cell's shape and are involved in intracellular transport and cell division.
Step-by-step explanation:
Actin filaments are present in the cell's cytoplasm, and the microtubules are present in the cell's cytoplasm. Therefore, the correct answer to the question is A) Cytoplasm, Cytoplasm. Actin filaments, or microfilaments, are composed of two intertwined strands of actin. They support the cell structure by concentrating just beneath the cell membrane and are involved in processes such as cell movement and muscle contraction. Microtubules are hollow cylinders made from polymers of alpha and beta-tubulin, originating near the nucleus at the centrosome. They maintain the cell's shape, facilitate intracellular transport, and are integral components of cilia, flagella, and the mitotic spindle during cell division.