Questions

In chemistry, the term transition metal has three possible meanings: The IUPAC definition defines a transition metal as "an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell".

Any of the set of metallic elements occupying a central block (Groups IVB–VIII, IB, and IIB, or 4–12) in the periodic table, e.g. iron, manganese, chromium, and copper. Chemically they show variable valency and a strong tendency to form coordination compounds, and many of their compounds are coloured.

Here in the given options, only iron (Fe) is a transition metal since Strontium is an alkaline earth, arsenic is a metalloid, hydrogen is (normally) a diatomic gas.

Absence of cell division is the process that never comes in interphase.

The study of statistics such as births, deaths, income, or the incidence of disease, which illustrate the changing structure of human populations.

In brief, Study of both quantitative and qualitative aspects of human population.

1. Quantitative aspects include composition, density, distribution, growth, movement, size, and structure of the population.

2. Qualitative aspects are the sociological factors such as education quality, crime, diet, development, nutrition, wealth and well being.

This 11.2 km/s is also known as the escape velocity. It works out to roughly 25000miles per hour 

Law of Octaves states that "If the chemical elements are arranged according to increasing atomic weight, those with similar physical and chemical properties occur after each interval of seven elements." That is every 8th element have the same physical and chemical properties. This was established by the British scientist John Newlands in the year 1865.