Which of the non-living things listed below, were once part of a living thing? 

Butter, Leather, Soil, Wool, Electric bulb, Cooking oil, Salt, Apple, Rubber

The non-living things that were once part of a living thing are

Butter - made from milk, obtained from dairy animals.

Leather - made from skin of animals.

Wool - made from fur of sheep.

Cooking oil - made from seeds of plants.

Apple - Fruit that grows on tree.

Rubber - made from latex obtained from trees.