Ism aur Uddeshya: Ek Aisa Farq To Nahin Laga Sakte?

Yaar samajh nahi aaya. Aaj class mein humne Ism aur Uddeshya ki baat ki thi. Lekin mein samajh nahin paya ki ve dono kya hain. Sir ne kaha ki ism ek pratyek tatva ka darshak hai, jabki uddeshya ek pratiyogita ya lakshya hai. Lekin fir bhi ye samajh nahi aaya ki ve dono aasani se alag nahi karte. Sir ne diya example tha ki 'swatantrata' ism hai, lekin 'swatantrata ki raksha' uddeshya hai. Lekin phir ismein swatantrata ka ism kya hai?