Answer:
Air drying
Explanation:
Sanitation is the set of measures that aims to preserve or modify the conditions of the environment in order to prevent diseases and promote health, improve the quality of life of the population and the productivity of the individual and facilitate economic activity. Basic sanitation is a right guaranteed by the Constitution as the set of services, infrastructure and operational installations for water supply, sanitary sewage, urban cleaning, urban drainage, solid waste and rainwater management.
Sanitation can be carried out in several ways, except for dry air, as this would damage the quality of sanitation and the environment.
Sanitation is important in treated water, sewage collection and treatment services lead to an improvement in the quality of people's lives, especially in child health, with a reduction in child mortality, improvements in education, in the expansion of tourism, in the valuation of properties, in income of the worker, in the cleaning of rivers and preservation of water resources, etc.
Scientific knowledge is based upon observation, and it is supplemented by experimentation.<span> Scientific research follows the scientific method, a four-step process that guides scientists in the accumulation of knowledge.</span>
Explanation:
It is given that,
The thinnest soap film appears black when illuminated with light with a wavelength of 535 nm, 
Refractive index, 
We need to find the thickness of soap film. The soap film appear black means there is an destructive interference. The condition for destructive interference is given by :

t = thickness of film
m = 0,1,2....
= refractive index


For thinnest thickness, m = 1


Hence, this is the required solution.
Answer:
C. lonic bonds involve the transfer of electrons between ions, while
Van der Waals forces involve the attraction of nonpolar molecules.
Explanation:
Just did it