The correct option is “Dioptre”. Power of lens is defined as the reciprocal of its focal length in meters. Power of lens is measured in Dioptre, represented by the symbol D.

 The speed of a sound is defined as the distance travelled by a rarefaction or compression per unit time. Therefore, it is given by, wavelength per unit time.

 DISPROPORTIONATION REACTION - disproportionation, sometimes called dismutation, is a redox reaction in which one compound of intermediate oxidation state converts to two compounds, one of higher and one of lower oxidation states.

In a plant the roots take in air present in the soil. Leaves have tiny pores called stomata through which they exchange gases. The breakdown of glucose in the plant cells is similar to that in other living beings.

A balanced diet means a meal which include carbohydrate, protein, fats and vitamins in requisite proportion. chapati, dal, vegetables together form a balanced diet.

Arthropoda is the largest phylum with 80% of all known living animals. Animals with jointed appendages (in Greek Arthron: jointed, poda: legs). The body has three segments/regions as head, thorax and abdomen. Body is covered by an exoskeleton made up of chitin. For example- Prawn, Housefly, Cockroach.

The correct sequence of parts of female reproductive organ in plants Stigma, Style, Ovary and Thalamus.

Phylum chordata’s All organism possess notochord (mesodermally derived rod-like structure), a dorsal hollow nerve cord and paired pharyngeal gill slits. For example- Frogs, Sharks, turtles, Human beings. In higher organisms, notochord is replaced by vertebral column. The pharyngeal gill slits are present for respiration. Tape worm belong to phylum Platyhelminthes

The correct option is “Transition metals”. The element gold lies in transition metals group. The transition elements are also known as d-block elements. Gold atomic number is 79 and its atomic mass is 196.97 amu.