General Science Mixed Quiz: Set 74

After 3 minutes 45 seconds the boy has completed seven and a half rounds, so he stands at the point exactly opposite his starting point.

Accelerators speed up the vulcanisation of rubber; they are not a part of paint.

Radiation carries heat as electromagnetic waves, and these waves travel even through empty space. Heat moves in three ways.

Capra hircus is the scientific name of the domestic goat, in which Capra is the genus and hircus the species, written in the two-word form that Carl Linnaeus gave to biology.

It gives the direction of the force on a current-carrying conductor placed in a magnetic field. Stretch the thumb, forefinger and middle finger of the left hand so that they are mutually perpendicular.

Pliers and scissors are each made of two arms joined at one rivet, and each arm is a complete class 1 lever, so the tool is called a double lever.

Water molecules are strongly polar, so they can pull apart the positive and negative ions of a salt and surround them.

Balance is controlled by the inner ear, which holds the vestibular apparatus alongside the organ of hearing. It is made of three semicircular canals set at right angles to one another and two small sacs, the utricle and the saccule.

A ribosome contains RNA, but it has no genes of its own; it reads messenger RNA sent from the DNA of the nucleus or an organelle.

The petiole is the stalk that joins a leaf blade to the stem; it belongs to the leaf, not to the flower, and a leaf without one is called sessile.

No pathway of respiration in living cells turns glucose into methanol. Glucose is first split in the cytoplasm into two molecules of pyruvate; this step, glycolysis, is common to all cells.

For the same pair of surfaces the order of friction is always static, then kinetic, then rolling. Static friction is the largest because the surfaces interlock while at rest and that grip has to be broken to start motion.

Platelets, or thrombocytes, gather at a cut and start the process that forms a clot and stops bleeding. Platelets are tiny cell fragments without a nucleus, broken off from large cells called megakaryocytes in the bone marrow.

Charles’s law says that at constant pressure the volume of a fixed mass of gas is directly proportional to its absolute temperature, so V by T stays constant.

Chemical messengers called neurotransmitters are released from the nerve endings, the tips of the axon, into the synapse. A nerve impulse travels from the dendrites through the cell body and along the axon as an electrical signal.

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.

HIV spreads through body fluids such as blood, semen, vaginal fluid and breast milk, not through droplets from coughing, sneezing or talking.

Plants need magnesium in fairly large amounts, so it is a macronutrient, not a micronutrient. Plant nutrients are grouped by how much of them a plant needs.

Each nucleotide of DNA is made of these three parts, and many nucleotides joined together form the polynucleotide chain. In a DNA strand, the sugar of one nucleotide is linked to the phosphate of the next by a phosphodiester bond, making a sugar-phosphate backbone.

Water is densest at 4 °C, where one cubic metre has a mass of almost exactly 1000 kg.