The analogy 'Cytoplasm is to cytosol as a swimming pool containing chlorine and flotation toys is to' is best completed with 'water.' 'Diffusion is to osmosis as endocytosis is to' would be 'phagocytosis'. And for the induced-fit model of enzyme-substrate binding, 'the fitting together of two jigsaw puzzle pieces' represents the process accurately.
The appropriate term that best completes the analogy "Cytoplasm is to cytosol as a swimming pool containing chlorine and flotation toys is to" is water. This is because the cytoplasm of a cell consists of cytosol, which is the liquid part, and other components such as organelles, similar to how a swimming pool consists of water and other items like chlorine and toys. The cytosol is like the water in the pool - it's the substance in which everything else is suspended or contained.
In the case of the analogy "Diffusion is to osmosis as endocytosis is to", phagocytosis is a fitting term, because osmosis is a specific type of diffusion concerning water across a semi-permeable membrane, just as phagocytosis is a specific form of endocytosis involving the cellular ingestion of particles
For the analogy question about enzyme-substrate binding models, the best choice is d. the fitting together of two jigsaw puzzle pieces. This is because the induced-fit model emphasizes the dynamic fit between the enzyme and its substrate, akin to how jigsaw puzzle pieces fit together in a specific manner.