Students investigate a radioactive source. They place a detector close to a radioactive source and take 5 readings over 5 minutes. They then place a thin sheet of paper between…

The diagram represents the molecule lecithin, a chemical that is added to chocolate drinks to prevent the oils separating out from water. Which row of the table below correctly identifies…

The diagrams below show part of the breathing apparatus of a human. Which row of the table correctly identifies the locations affected by two chemicals found in cigarettes and by…

The design in the diagram is formed from four circles which all touch at the top of the shape (the diagram is not to scale).The diameter of the smallest circle…

Nuclide XNR is an unstable isotope which decays in two stages into nuclide Z as shown:What are the values of P and Q? Answer: 3) B When an atom decays…

2.74g of 1-bromobutane is reacted with excess aqueous sodium hydroxide to produce 1.11g of butan-1-ol according to the equation below.C4H9Br + NaHO → C4 H9OH + NaBrWhat is the percentage…

Which of the following could result in a homeostatic response?1 A rise in an internal condition.2 A reduction in an internal condition.3 A rise in an external condition.4 A reduction…