Which part of the flower is collectively known as the stamen?

The stamen is the male reproductive part of the flower, and it is made up of two distinct structures: the anther and the filament. The anther is responsible for producing pollen, which contains the male gametes, while the filament serves as a supportive stalk that holds the anther in place. Together, they constitute the stamen, playing a crucial role in the fertilization process of flowering plants.

In contrast, the options involving the ovary and style, petal and sepal, or stigma and ovule refer to different parts of the flower. The ovary and style are components of the pistil, which is the female reproductive structure. Petals and sepals are parts that typically serve to attract pollinators and protect the flower, respectively, and the stigma and ovule are also parts of the female reproductive system. Thus, the focus on the anther and filament establishes why this option accurately represents the stamen.