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.
All of the above points are valid for fossils' contributions in understanding the process of evolution. They allow us to study the ancestry, we can see the homologous organs or structures, if fossils are well-preserved; different fossils can lead us to follow the cycles of the changes that occurred during macroevolutions, and fossils can be used to study different populations which had different body structures for surviving in different environmental conditions.
Gametes develop in the multicellular haploid gametophyte (from the Greek phyton, “plant”). Fertilization gives rise to a multicellular diploid sporophyte, which produces haploid spores via meiosis. This type of life cycle is called a haplodiplontic life cycle
