2 sentences

1. 指甲和头发的主要成分是角质。

   zhǐ​jia hé tóu​fa de zhǔ​yào chéng​fèn shì jiǎo​zhì.

   Keratin is the main component of nails and hair.

   Source: Dong Chinese Dictionary

2. 植物叶片表面的角质可以减少水分蒸发。

   zhí​wù yè​piàn biǎo​miàn de jiǎo​zhì kě​yǐ jiǎn​shǎo shuǐ​fèn zhēng​fā.

   The cuticle on the surface of plant leaves can reduce water evaporation.

   Source: Dong Chinese Dictionary