Very interesting problem!
On first reading, it sounded impossible. Tom has normal vision, and there are no male carriers for x-linked recessive disorders. So the daughter can at best (or worst) be carrier of the disorder.
We are told that the daughter has the disorder, but the daughter can only be a carrier with genotype XBXb.
We are also told that Turner Syndrome, which is a disorder related to the x-chromosome. Half of those affected have one of the x-chromosomes missing (monosomy), and some others have some cells with missing or deformed x-chromosomes (mosaicism). Under these circumstances where the normal chromosome is missing, the X-linked recessive Xb allele will be expressed, hence even a carrier can express the red-green colour-blindness.
From the pedigree chart, we can deduce that the colour-blindness must be inherited from Jill, the mother. Tom with normal vision cannot be a carrier because X-linked recessive disorders do not have male carriers.
The daughter's colour-blindness is derived from two sources,
1. inherited Xb allele from mother Jill
2. Turner syndrome that allowed the single allele to express colour-blindness.
Answer:
Eukaryotic cells arose through endosymbiotic events that gave rise to the energy-producing organelles within the eukaryotic cells such as mitochondria and chloroplasts. ... The endosymbiotic theory proposes that one organism engulfed another, and the two co-evolved together until they could not exist independently.
Explanation:
<span>Eutrophication (the overenrichment of aquatic ecosystems with nutrients leading to algal blooms and anoxic events) is a persistent condition of surface waters and a widespread environmental problem. Some lakes have recovered after sources of nutrients were reduced. In others, recycling of phosphorus from sediments enriched by years of high nutrient inputs causes lakes to remain Eutrophic even after external inputs of phosphorus are decreased. Slow flux of phosphorus from Overfertilized soils may be even more important for maintaining eutrophication of lakes in agricultural regions. This type of Eutrophication is not reversible unless there are substantial changes in soil management. Technologies for rapidly reducing phosphorus content of over-enriched soils, or reducing erosion rates, are needed to improve water quality.</span>