Students are each given a 20 gram sample of an unknown solid compound in a clear plastic bag. they are instructed to break the material into smaller parts by gently hitting it with a hammer. some of the parts break into large chunks and some look like a fine powder.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.

some scientists like gregory adcock agree with thorne's theory of regional continuity.

others, like chris stringer and ian tattersall, believe thorne's results may be contaminated or misinterpreted.

it is a limiting nutrient limited by a single nutrient in the ecosystem, & the single goes very slow.