sexual union

Sexual union is a normal part of the life cycle for most animals.

交配对大多数动物来说是生命周期中正常的一部分。

The zoo's breeding program relies on carefully timed sexual union between the pandas.

动物园的繁育计划依赖于这对熊猫之间精心安排的交配。

Many insects have very brief sexual union that lasts only a few seconds.

许多昆虫的交配非常短暂，仅持续几秒钟。