Two black-fur mice are bred, and have the litter shown below. What is the most likely explanation for the presence of the white-fur offspring?

That the parents are heterozygous for the hair colour gene

Explanation:

Because they are both black, black must be a dominant gene, the parents must have one white gene/one black gene because the white rat would have to get two white genes

it would be c. xylem.

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.