1.c. 1) This prohibition applies not only to food, but also, for example,
a) to the crumbling of a clod of earth,
b) to the chopping of wood into small chips and
c) to the sawing of wood for the purpose of making sawdust.
2) There may well be several prohibitions involved in one activity; for instance, if one crumbles a clod of earth, one is usually also transgressing the prohibition against moving earth on Shabbath. (See Chapter 20.)
3) See also Chapter 15, paragraphs 28 and 40.