The average salinity of sea water is 3.5% or 35 parts per thousand. In other words, for every 1 litre of sea water there is 35 grams of dissolved salts (NaCl) .

The social animal among the options is:

(A) Bee

Explanation:

Bees are known for their highly organized and social behavior. They live in colonies where individuals have specific roles such as workers, drones, and a queen. They communicate with each other, work together for the common good of the colony, and have a complex social structure. In contrast, mosquitoes, bur (assuming it refers to burrowing animals), and domestic flies are not typically considered social animals in the same way as bees. Bees, especially honeybees, are well-known for their intricate social organization and cooperation within the colony.

Entomology is the scientific study of insects. It involves the examination of the biology, behavior, ecology, taxonomy, physiology, and evolution of insects. Entomologists, the scientists who specialize in this field, study a vast and diverse group of organisms, which make up the largest class of animals on Earth. The knowledge gained through entomology has wide-ranging applications, from understanding ecosystems and biodiversity to pest management and forensic entomology.

All of these diseases are caused by bacteria i.e. Pneumonia, Cholera, Tuberculosis. Cancer is caused by uncontrolled cell division. Pneumonia is caused by a bacterium Streptococcus pneumoniae. Cholera is caused by a bacterium Vibrio cholerae.

In a generator, a rotating magnetic field is used to produce electrical energy. When a conductor, such as a wire, moves through a magnetic field, a voltage is induced across the conductor. This is known as electromagnetic induction, and it is the fundamental principle behind how generators work.