Which two of the following statements about genetic variation are correct?1 Asexual reproduction always produces genetic variation.2 Gamete production is the only possible source of genetic variation in sexual reproduction.3…

A 100% efficient ideal transformer has 400 turns on its primary coil and 100 turns on its secondary coil. The input voltage across the primary coil is 240 V. An…

Diborane has the formula B2H6.Assume that boron consists of two isotopes, containing 20% B105 atoms and 80% B115 atoms,and that all hydrogen atoms are H1.Molecules of diborane will therefore have…

A student carried out tests to find out which molecules were present in a sample of urine from a human male. The student recorded the presence of large protein molecules…

A cross-country running track is in the shape of a regular pentagon. Competitors run clockwise around the track. When on the third leg of the course they run on a…

A water jet pack has lifted a person vertically upwards, as shown in the sketch. He is now stationary at a constant height. Water rises through the tube and is…

Complete combustion of 35 cm3 of a straight-chain alkane vapour gave 105 cm3 of carbon dioxide gas. Both gas volumes were measured at the same temperature and pressure. Which of…

Which of the following statements is/are correct for a healthy human?1 A protein section coded for by part of a gene consisting of 500 base pairs will have a maximum…

To get to work, Sylvie first catches a bus and then catches a train.The probability that the bus is on time is 0.6The probability that the bus is late is…

Cosmologists have deduced that soon after the Universe was formed it was filled with electromagnetic radiation in the form of intense gamma-rays. They have also deduced that the Universe has…