General Science Mixed Quiz: Set 90

This is false, because variations differ in how well they suit the environment, and that difference is the basis of natural selection.

Red biotechnology is the branch applied to medicine and health care, including the making of insulin, antibiotics and vaccines. Biotechnology is often divided by colour according to its field of use.

Furnace oil is a heavy refinery product, it is burnt by industry for heat and power, and its high sulphur content makes it a polluting fuel.

A beam seen from the side is visible only because tiny particles send some of its light sideways. Light travelling in a straight line cannot enter our eyes unless something redirects it towards us.

The adult skeleton has eighty bones in the axial part, that is the skull with the ear ossicles and hyoid, the vertebral column, the ribs and the sternum, and one hundred and twenty-six in the appendicular part, that is the limbs with the pectoral and pelvic girdles, making two hundred…

Rotational kinetic energy is ½Iω², and the ring has the larger moment of inertia. For a thin ring about the axis through its centre and perpendicular to its plane, all the mass sits at distance R, so I = MR².

Sertoli cells line the seminiferous tubules and provide nutrition and support to the germ cells as they divide and change into sperms, which is why they are called nurse cells; they are controlled mainly by follicle stimulating hormone.

Together the two resins take out every dissolved ion, which leaves demineralised water. In the cation exchange resin (written RH), metal ions such as Ca2+, Mg2+ and Na+ are swapped for H+ ions.

X-rays have wavelengths from about 0.01 nm to 10 nm, so 1 nm lies well inside the X-ray band. In the electromagnetic spectrum, wavelength decreases from radio waves through microwaves, infrared, visible light and ultraviolet to X-rays and gamma rays.

Jupiter is a planet; it does not make its own light and shines only by reflecting sunlight. A luminous object produces light of its own, as stars do by nuclear fusion in their cores, where hydrogen is turned into helium.

High pressure pushes the gas molecules close together and low temperature slows them down, so the attractive forces can hold them as a liquid.

The anther is the top part of the stamen, the male organ of a flower, and pollen grains form inside it.

The de Broglie wavelength depends only on momentum, so equal wavelengths mean equal momenta. In 1924 Louis de Broglie proposed that every moving particle has a wave linked to it, with wavelength λ = h/p, where h is Planck's constant and p is the linear momentum.

If pressure is proportional to temperature for a fixed amount of ideal gas, the volume must stay constant, so the process is isochoric.

Natural chlorine is a mixture of two isotopes, and their weighted average is about 35.5 u. Chlorine has two stable isotopes: chlorine-35, which makes up about 75 per cent of natural chlorine, and chlorine-37, about 25 per cent.

Crown gall is caused by the bacterium Agrobacterium tumefaciens, which enters through a wound near the base, or crown, of the stem and makes the plant grow rough tumour-like swellings there.

The endodermis is the innermost layer of the cortex that surrounds the vascular tissue; it is not a part of the vascular bundle itself.

Cerium oxide (CeO2) strongly absorbs ultraviolet rays while letting visible light through, so it is added to glass to make it UV-protective.

It is the innermost of the three ear ossicles of the middle ear and is shaped like a stirrup; it passes vibrations from the incus to the oval window of the inner ear and is the smallest bone of the body.

The acrosome is a cap-like structure over the sperm nucleus filled with enzymes that digest the layers around the egg so that one sperm can fuse with it.