ova

例句：

1. 1. The female bird laid an ovum in the nest.
   这只雌性鸟在巢里产了一个卵。
2. 2. The ovum was fertilized by a male bird.
   这个卵由一只雄性鸟受精。
3. 3. Ova are the basic building blocks of life.
   卵是生命的基本构成单位。