progressions

In hydrogen fluoride, hydrogen atom is bonded to highly electronegative atom, fluorine (electronegativity = 4). It has been found that in solid state hydrogen fluoride consists of long zig-zag chains of H-F molecules associated by H-bonds. On heating, progressively, the length of th..

He bought a book yesterday. (past time) He left for Paris last year. (past time) They sang songs at the wedding. (past time) We were playing on the hill. (past time) Each tense has a simple form indicating action, a progressive form, indicating ongoing action; a perfect form,..

If three quantities are in harmonic progression, then the middle quantity is called the harmonic mean between the other two. Example: 1/3, 1/7, 1/11 are in H.P., then 1/7 is the middle term. Hence 1/7 is the harmonic mean between 1/3 and 1/1..

Major progress in understanding magnetism came after the relationship between electricity and magnetism was established by Hans Christian Oersted in 1820. He found that an electric current moves a compass needle and this effect lasts as long as the current flows through the wire. It is th..

This was proposed by Weismann who did not agree with Lamarck's theory of inheritance of acquired characters. To prove his point, he cut off the tails of many successive generations of mice. This resulted in forced disuse of the tail. According to the theory of use and disuse, the tails should have..

Harmonic Mean (H.M.) - If three quantities are in harmonic progression, then the middle quantity is called the harmonic mean between the other two. Example: 1/3, 1/7, 1/11 are in H.P., then 1/7 is the middle term. Hence 1/7 is the harmonic mean between 1/3 and 1/1..

Magnetic Effect of Electric Current - Major progress in understanding magnetism came after the relationship between electricity and magnetism was established by Hans Christian Oersted in 1820. He found that an electric current moves a compass needle and this effect lasts as long as the cu..

All living organisms need food for growth, work, repair and maintaining life processes. Food is made up of several components such as proteins, carbohydrates, fats, minerals and vitamins. Each of these components is required in a specific amount because each of them has a definite role to play in t..

Growth is an irreversible increase in size and weight of an organism. The cells of the body do not grow uniformly but differentially. The main types of growth are auxetic, multiplicative and accretionary. The human growth curve is sigmoid and is controlled by hormones. Regeneration is of two types...

The Animal Kingdom is divided in several phyla mainly on the basis of the cell organisation, symmetry, presence or absence of notochord and body cavity. Animals are arranged progressively from simple single-celled protozoans to highly complex mammals. Given below are some of the main cha..