sex characteristic

例句：

1. 1. The study ofsex characteristics is important for understanding human behavior.
   研究性别特征对于理解人类行为非常重要。
2. 2.The researcher found that the sex characteristicsof the species were significantly different from thoseof other animals.
   研究者发现，该物种的性别特征与其他动物显著不同。
3. 3. The sexcharacteristics of the new species have beenstudied extensively in recent years.
   近年来，对新物种的性别特征进行了广泛的研究。