General Science Mixed Quiz: Set 106

For an object launched horizontally, the time of fall depends only on the height, because its starting vertical speed is zero.

Meiosis makes gametes that differ from one another, and fertilization joins a gamete from each of two parents, so every offspring gets a new mix of genes.

At this one temperature the Celsius and Fahrenheit scales show the same number. The two scales are linked by F = (9/5)C + 32.

Above the threshold, the kinetic energy of the ejected electrons rises as the frequency of the light rises, so the statement that it does not change is wrong.

The air we breathe out carries carbon dioxide, which reacts with limewater to form a white, insoluble solid that makes it look milky.

Marie Curie discovered radium; the first two pairs have their discoveries swapped. Marie Curie and Pierre Curie discovered the radioactive elements polonium and radium in 1898, and Marie Curie went on to win Nobel Prizes in both physics (1903) and chemistry (1911).

Iron is needed to make haemoglobin, so too little iron means too little haemoglobin and a reduced ability of the blood to carry oxygen.

Marsilea is a water fern, a pteridophyte, and pteridophytes are the first land plants with true vascular tissues, xylem and phloem.

Green plants use sunlight, carbon dioxide and water to make glucose, giving out oxygen as a by-product. Photosynthesis takes place mainly in the chloroplasts of leaf cells, where chlorophyll traps light energy.

A mixture of carbon monoxide and hydrogen is called synthesis gas, or syngas, because it is the starting material for making methanol and many other compounds.

Sodium is so reactive that carbon cannot reduce its compounds, so it is obtained by passing electricity through molten sodium chloride.

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.

Plastics are long chains of carbon atoms joined by strong covalent bonds, which water, air and most microbes cannot easily break.

In a class 3 lever the effort is applied between the fulcrum and the load, so the effort always sits nearer the fulcrum and its arm is the shorter of the two.

Each of the three groups includes species that carry toxins in their bodies to deter predators. Butterflies: the Monarch butterfly feeds as a caterpillar on milkweed and stores its bitter cardiac glycosides, so birds that eat it fall sick; its bright orange colour is a warning.

An ion-exchange resin or zeolite swaps the calcium and magnesium ions that cause permanent hardness for sodium or hydrogen ions.

Streptococcus mutans turns dietary sugar, especially sucrose, into a sticky slime that glues it to the teeth. The bacterium makes enzymes called glucosyltransferases that join the glucose units of sucrose into sticky chains called glucans.

Genetic modification is used in plants, animals and microbes alike, so this statement is false. A genetically modified organism is one whose DNA has been changed, usually by taking a useful gene from one organism and putting it into another.

Ethylene is the only gaseous plant hormone, and it raises the rate of respiration in climacteric fruits such as banana, mango and tomato, so a single ripe fruit speeds up the ripening of those around it; the compound ethephon releases ethylene and is used in orchards for uniform ripening.

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.