Railway Science (Environment – Ecosystem & Ecology)

Total Questions: 23

21. Which of the following is the unit of measurement of the "Ecological Footprint" ? [RRB JE 26/05/2019 (Afternoon)]

Correct Answer: (d) Global Hectare
Solution:

The Ecological Footprint - It is a resource accounting tool that measures how much biologically productive land and the sea is used by a given population or activity and compares this to how much land and the sea is available.
The Idea of Ecological Footprint was given by William Rees in 1992. Carbon Footprint - Total volume of greenhouse gases resulting from everyday economic and human activity.

22. The basic source of biological diversity is ______. [RRB Group D 31/10/2018 (Morning)]

Correct Answer: (b) mutation
Solution:

Mutation is a phenomenon which results in alteration of DNA sequences and consequently results in changes in the genotype and the phenotype of an organism. In addition to recombination, mutation is another phenomenon that leads to variation in DNA.

23. _____ gas was not present in its free state when life arose on Earth. [RRB Group D 02/11/2018 (Afternoon)]

Correct Answer: (d) oxygen
Solution:

Earth’s original atmosphere was rich in Methane, Ammonia, Water vapour, and the noble gas neon, but it lacked free oxygen. Oxygen is a colorless, odorless and tasteless gas. It supports life. It is noncombustible, but will actively support the burning of combustible materials.Pure oxygen is non flammable. The air in Earth's atmosphere is made up of approximately 78% Nitrogen, 21% Oxygen and 1% other gasses.