Bio accumulation of DDT lead to bird eggs with weak shells and non viable offspring. The lethal effects of DDT on birds was first noted in 1950; scientists discovered that earthworm was accumulating the DDT pesticide and that the robins that were preying on the earthworms were been poisoned. Further research revealed that the chemical cause thinning of the egg shell and production of non viable offspring. The chemical has since been banned in USA.
Answer:
In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection. ... Evolution relies on there being genetic variation in a population which affects the physical characteristics (phenotype) of an organism.
Explanation:
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Answer:
The nucleus, cell membrane and cytoplasm.
Explanation:
The nucleus, cell membrane and cytoplasm are three elements that cannot be absent in a cell because they are necessary for the survival of the cell. The nucleus controls and regulates the activities happening inside the cell e.g. growth and metabolism etc. Cell membrane acts as a wall to protect the inner part of the cell from the external environment as well as allows nutrients and gases inside and outside the cell. Cytoplasm serves as a medium for the conduction of nutrients and waste from on place to another and also for the medium for organelles in which they floats.
The kingdoms that include both unicellular & multicellular are protist & fungi
