\[ \textbf{Fertilization in angiosperms} \text{ occurs when pollen grains land on the stigma, germinate, and the pollen tube carries sperm to the ovule for fertilization.} \] Post-fertilization structures: \[ \begin{array}{|c|c|} \hline \textbf{Structure} & \textbf{Transformation} \\ \hline \text{Zygote} & \text{Develops into an embryo} \\ \text{Endosperm} & \text{Provides nourishment to the developing embryo} \\ \text{Ovule} & \text{Becomes the seed} \\ \text{Ovary} & \text{Matures into the fruit} \\ \hline \end{array} \]
(b) Order of the differential equation: $ 5x^3 \frac{d^3y}{dx^3} - 3\left(\frac{dy}{dx}\right)^2 + \left(\frac{d^2y}{dx^2}\right)^4 + y = 0 $