Questions

The expansion of the rail networks led to better transport system for trading between many parts of the nation and the steel is the main component in making the rails and the locomotive itself resulting in the growth of the steel industry.

It is a collection of routers under the control of a single administrative authority and that uses a common Interior Gateway Protocol

Parvovirus B19 causes severe anemia because it preferentially infects erythrocyte precursors.

a. Parvovirus B19 binds preferentially to the erythrocyte blood group P antigen on erythroid precursor cells.

Answers B, C, D are incorrect:

b. after entry the single-stranded viral DNA genome is transported to the cell nucleus where the host DNA polymerase synthesizes the complimentary DNA strand.

c. Parvovirus B19 infection can be diagnosed by direct detection of viral DNA not RNA.

d. the fetus of a seropositive mother is protected from infection by maternal circulating antibodies.

We know that most of the metals are goof conductors of electricity and heat. Metals are very strong but they are malleable i.e, they can be bent into a shape. These are shiny when they are cut or polished. 

Hence, metals are malleable, conductors and luster. All the above are properties of the metals.

The calm centre of the anticyclonic gyre in the North Atlantic, comprising a large eddy of surface water, the boundaries of which are demarcated by major current systems such as the Gulf Stream, Canaries Current, and North Atlantic Drift. The Sargasso Sea is a large, warm (18°C), saline, which is characterized by an abundance of floating brown seaweed (Sargassum).

Kelvin temperature scale is the temperature scale that is based upon absolute zero.

An atom is the smallest particle of a substance. Chemical substances are divided into two major groups. They are

1. Pure Substances (and)

2. Mixtures.

There are two types of pure substances that are Elements and Compounds.

Elements : An element is a substance that is made up of only one kind of atoms and cannot be broken down into simpler substances by chemical means. Metals and Non- metals come under elements.

Examples of elements are Iron, Silver, Gold, Mercury etc.

Compounds : A Compound is a substance that is formed when two or more elements combine chemically.

Examples of compounds are Water, Carbon dioxide, methane, vinegar etc.

Mixtures : A Mixture is formed when two or more substances mixed together but not chemically combined.

Example: Air.