Final answer:
After a plant dies, it decays and becomes part of the soil, enriching it and allowing for nutrient recycling. Dead plants do not turn into gas, immediately become new plants, or remain the same indefinitely.
Step-by-step explanation:
After a plant dies during winter, it typically undergoes a process of decay and becomes part of the soil, which is option a. This natural process allows for the nutrient recycling necessary for other organisms and plants to thrive. The dead plant tissue decomposes with the help of various organisms such as bacteria and fungi, which break down the complex organic materials. This releases nutrients back into the soil, enriching it and promoting the growth of new plants.
Despite the cold temperatures, not all plants die in the winter. Some enter a state called dormancy, where their metabolic processes slow down, and they conserve energy until favorable conditions return. However, for those that do not survive, they will not quickly turn into a gas, immediately become a new kind of plant, or stay the same forever, eliminating options b, c, and d. Some plants also have adaptations such as deep roots, fleshy leaves, or dormant seeds to help them survive unfavorable conditions.