Daily NEET MCQ- June 24, 2022 - NEET MCQ

One mole is the amount of a substance that contains as many particles as there are atoms in exactly 12 g of the carbon atom. So S.I. the system took mole as the seventh base fundamental quantity (symbol = mol).

Avogadro number denoted by N_A. Its value is 602213670000000000000000, also written as 6.022×10²³. It’s the number of entities in 1 mol of a substance. The units may be electrons, atoms, ions, or molecules, depending on the nature of the substance.

One mole of any substance contains Avogadro’s number of particles. Its value is 6.022×10²³ atoms. But here it’s given 12.044 x 10²³ atoms, thereby dividing it by Avogadro’s number; 12.044 x 10²³ atoms/6.022×10²³ atoms = 2 moles. Hence it contains 2 moles of oxygen.

The number of significant digits is 6. The zeros after the decimal are also significant.

The correct answer is 5. While calculating the number of significant digits, we need not consider the zero preceding 2.

According to the rounding off rules, if the digit to be removed is 5 and the following digit is not zero, then the last remaining digit is increased by one.
Given number = 75.66852
After applying rounding rules, 852 rounds off to 9
Hence, the final answer will be “75.669”.

Plant cells contain an extra layer outside their cell membrane called cell wall. Cell wall plays a major role in the metabolic activities of a plant cell. It helps in controlling of osmotic pressure.

Artificial classification is based on morphological structures of the plant i.e. artificial classification focuses on external structure of the plants than their internal structure.

Phylogenetic classification considers evolutionary relationships between organisms. Fossil records, cytotaxonomy, chemotaxonomy and numerical taxonomy help in studying their evolutionary structures.

Numerical classification is based on mathematical calculations based on observable characteristics. In this mode of classification, each character is given a number or a code. The more the number of similar characters, the more is the chance that they belong to similar taxon. The main disadvantage of numerical taxonomy comes with the variation in result with variation in set of characteristics.