Not sure this is a question but my answer would be a semi-permeable membrane? Hope this helps! <3
Answer:
In simple cuboidal epithelium, the nucleus of the box-like cells appears round and is generally located near the center of the cell.
Answer:
Due to mixing of particles present in the upper layer of limestone with sandstone during deposition.
Explanation:
The parent layer was limestone layer which is older than sandstone layer. This sandstone layer spreads on the limestone layer because of wind. The wind moves these sandstone from other region and their deposition occurs on the limestone layer. During deposition of sandstone, some particles of limestone which are present at the surface mixes with the sandstone so that's why in sandstone layer, small and weathered pieces of limestone are present.
