Which describes a Mendelian trait? A. Humans can have a variety of shoe sizes.
B. Humans can have dimples or no dimples.
C. There are many different skin colors for humans.
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D. Human height is controlled by many genes.

D. Human height is controlled by many genes.

Explanation:

Human height is controlled by many genes. describes a Mendelian trait.

Height is a model trait that is controlled by variant of genes and not by only one gene. Height is a contribution of many genes because the height of a body consists of different body parts, such as the torso, leg bones, and even the neck.

Hence, the correct option is "D".

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.