This is because toxins are ingested by organisms and accumulate in the fatty tissues. Theses toxins then become more concentrated in successive trophic levels of a food web biological magnification. Magnification occurs because the biomass at any given trophic level is produced from a much larger biomass ingested from the level below and therefore, top-level carnivores tend to be the organisms most severely affected by toxic compounds.
Inadequate dietary vitamin D or its deficiency leads to malabsorption of calcium. Nutritional disorder leads to the rare disease rickets, which causes bones to become soft and bend in children. In adults, vitamin D deficiency leads to osteomalacia, which causes weak bones, bone pain and muscle weakness.
The body needs vitamin D to properly absorb calcium and phosphorus from the diet. However, keeping the right quantities of calcium and phosphorus in bones is challenging when vitamin D levels are low.
The two sources of vitamin D are-
- Natural sunlight
- Foods such as fish oil, Egg yolk and fatty fishes like salmon and mackerel
There are other disease conditions which lead to poor absorption of vitamin D-
- Inflammatory bowel disease
- Celiac diseases
- Kidney problems
To learn more about Rickets here-
brainly.com/question/26292489
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Please dont cheat your way through medical school
The youngest would be the ones at the top and the oldest would be at the bottom. the oldest is B and the ones around it, as they get bigger get younger. hope this helps :)