General Science Mixed Quiz: Set 171

On a hot day the air just above a road or desert sand is much hotter, and so optically rarer, than the air higher up.

Thermocol is polystyrene expanded with a blowing agent so that the solid becomes a rigid foam of tiny closed cells.

A direction in space needs two angles, one in the horizontal plane and one in the vertical plane, and declination and inclination supply exactly these.

In binomial nomenclature the first word of the name is the generic name, the genus to which the organism belongs, and the second is the specific epithet; thus Panthera is the genus that also holds the lion as Panthera leo and the leopard as Panthera pardus, while tigris is the…

Dalton held that the atom is the smallest, indivisible particle of matter, so his theory cannot explain particles inside the atom.

A tendon is a cord of white fibrous connective tissue, with very little elasticity, that transmits the pull of a contracting muscle to the bone it moves; the Achilles tendon at the heel is the best known example.

Hydrogen shows 0, +1 or -1 depending on what it is bonded to. In the free element H2 its oxidation number is 0, as for every element in its uncombined state.

Rising oestrogen from the ripening follicle triggers a sharp rise in LH from the anterior pituitary in the middle of the cycle, and this surge bursts the mature Graafian follicle and releases the ovum.

Potassium permanganate, KMnO₄, forms dark purple crystals that contain no water of crystallization; its formula has no attached water molecules.

The liver needs vitamin K to make prothrombin and several other clotting factors, so a deficiency of it lengthens the clotting time and causes bleeding; this is why a newborn is given vitamin K and why the vitamin is sometimes called the anti-haemorrhagic vitamin.

When copper is left in moist air for a long time, it slowly reacts with oxygen, water vapour and carbon dioxide.

Making a genetically modified organism needs all three steps: find the useful DNA, put it into the host, and make sure the host keeps it and passes it on.

Vegetable oils are hardened into margarine and vanaspati ghee by hydrogenation. Liquid vegetable oils are unsaturated: their fatty-acid chains contain carbon-carbon double bonds.

In the core of the Sun, at a temperature of about fifteen million kelvin, four hydrogen nuclei combine through the proton-proton chain to form one helium nucleus.

This is the fluid mosaic model of the cell membrane given by Singer and Nicolson in 1972. Each phospholipid has a water-loving (hydrophilic) phosphate head and two water-fearing (hydrophobic) fatty acid tails.

Red blood cells are produced in the red bone marrow, lose their nucleus on maturing and survive roughly four months, after which they are broken down in the spleen, which is accordingly called the graveyard of red blood cells; the iron released from their haemoglobin is used again.

At about 6 to 7 metres in an adult, the small intestine is by far the longest part of the alimentary canal.

Sleeping sickness, or African trypanosomiasis, is caused by the protozoan parasite Trypanosoma brucei, which is spread by the bite of the tsetse fly.

Light, small and dry pollen is a feature of wind-pollinated plants, not of plants that depend on insects. Insect-pollinated (entomophilous) flowers have to attract a visitor and then make the pollen travel on its body.

Evaporation is a surface process, so its rate depends on conditions at the surface of the liquid, not on how much liquid there is in total.