Tsar nicholas ii and tsarina alexandra were the romanov rulers of russia when the bolshevik revolution took place in 1917. during this revolution, tsar nicholas ii was overthrown, and the majority of his family members were killed. the remains of two of the tsar and tsarina’s children, alexei and anastasia, were never found. suppose two people came forward who claims to be the missing romanovs. which technology could only be used to identify alexei? dna technology str analysis mtdna analysis y-chromosome analysis

Option D, Y-chromosome analysis

Explanation:

In this technique, DNA is analysed in a way to study the hierarchical progression of Y chromosomes in the males . This methodology help in identifying the family background of any individual based on his/her gene analysis.

The Y chromosome is passed on from one generation to another  in sons as sons have one Y chromosome and one X chromosome while daughters have two X chromosome one from the father and the another one from the mother.

It is convenient to study the Y chromosomes in male to identify the family background.

Hence option D is correct

gold i'm pretty sure i might be wrong

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.