pure-breeding

例句：

1. 1. The pure-bred pedigree dog is a rare breed of dogs.
   纯种的纯种犬是一种稀有的犬类。
2. 2. Pure-breeding has been banned in many countries due to concerns over genetic defects.
   由于对遗传缺陷的担忧，许多国家禁止了纯种繁育。
3. 3. Pure-breeding is essential for the survival and development of certain species.
   对于某些物种的生存和发展来说，纯种繁育是必要的。