Which soil layers comprise the topsoil?

How does land development destroy ecosystems? it increases human carrying capacity too rapidly. it converts them into residential or agricultural areas. it forces humans to import non-native plants and animals. it expands the natural range of native wildlife species.

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

What organelle other than the nucleus houses dna in a eukaryotic cell?