Skin - Protects against microbes, 2 Physical barriers - Skin and tiny hairs in our breathing system, 2 Chemical barriers - Acid in stomach and antispectic in tears, Cilia - Tiny hairs in breathing system, Mucus - Traps microbes and dirt,

Papan Peringkat

Gaya visual

Pilihan

Berganti templat

Pulihkan simpan otomatis: ?