In the "herd" strategy for immunization, vaccinations are given . only to individuals who are most likely to be exposed to a disease only to individuals who travel to countries where certain disease are a threat to a large majority of the population the entire population

C. to a large majority of the population.

Explanation:

Immunization can be defined as the process of boosting an individual's immunity or immune system against antigens (immunogen) which cause diseases by the administration of vaccines.

Basically, immunization helps to improve the functions of the antibodies, B cells, T cells etc.

In the "herd" strategy for immunization, vaccinations are given to a large majority of the population in order to protect and prevent the spread of an infectious disease to those who are not immune.

answer: the direction of the wind is expressed as the direction from which the wind is blowing. for example, easterly winds blow from east to west, while westerly winds blow from west to east.

explanation:

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.