SAT (Stage-1) Mock Test - 29

Cl has 7 valence electrons and valency 1.
Hence this is the correct option.

Li has 1 valence electron and valency is 1.
P has 5 valence electrons and valency is 3.
Mg has 2 valence electrons and valency is 2.

The melting point decreases down a group.
Among the alkaline earth metals the decreasing order of melting points is Be, Mg, Ca, Sr, Ba.

The nucleus of every living cell contains deoxyribonucleic acid or DNA has specific genetic information and controls every feature of the body such as colour, looks, etc.

Acidity of a base is the number of hydroxyl ions which one molecule of the base can furnish in its aqueous solution.
NaOH and NH₄OH are monobasic.
Ca(OH)₂ is dibasic.
Fe(OH)₃ is tribasic.

Sodium hydroxide is used in the production of rayon.
Rayon was the first semi-synthetic fibre obtained by treatment of wood pulp with NaOH.
It has a silk like sheen and so it became popular as artificial silk.

Cell membrane consists of the lipid bilayer with embedded proteins. Hence these two are required for the structural integrity of the cell membrane.

Vacuole has single membrane, whereas nucleus, mitochondrion and chloroplasts have two membranes. Thus, 'vacuole' is the odd one.

This pair is correctly matched as Pulmonary artery carries deoxygenated blood from the right ventricle of heart towards the lungs for oxygenation.

Poikilothermic animals are cold-blooded animals in which their body temperature varies with environmental temperature. Homeothermic animals are warm-blooded animals in which temperature remains constant. Pisces and Amphibians are Poikilothermic animals & Aves and Mammals are Homeothermic animals. Hence it is correct option.

Auxin is a plant hormone responsible for controlling the direction of growth of root tips and stem tips in response to different stimuli including light and gravity.

In pond ecosystem, biomass of consumers is greater than biomass of producers. Such a pyramid is inverted.

Hydrogen gas is not responsible for heating earth`s surface and atmosphere.More generally, molecules that can acquire a charge asymmetry by stretching or flexing (CO₂, H₂O, N₂O, O₃, hydrocarbons...) are greenhouse gases; molecules that cannot acquire charge asymmetry by flexing or stretching (N₂, O₂, H₂) are not greenhouse gases.

World Environmental Day is celeberated on June 5.

Calcitonin polypeptide hormone is produced in humans primarily by the parafollicular cells (also known as C-cells) of the thyroid apart from thyroxine and triiodothyronine.