Taigas have few native plants besides conifers. The soil of the taiga has few nutrients. It can also freeze, making it difficult for many plants to take root. The larch is one of the only deciduous trees able to survive in the freezing northern taiga.
The hydrosphere refers to the water on the earth crust. If there were no hydrosphere, we would not have lakes, oceans, rivers, or even a hose full of water.