Natural selection arises as a result of?
Which of the following statements is not Lamarck's postulate on evolution?
A sample of human blood was put in a test tube and allowed to spin in a centrifuge. The components of the blood sample were clearly separated.
(a) List the four main components of blood that would be in the test tube.
(b) Name the component of the blood that: (i) would form the top layer in the test tube, (ii) destroys pathogens; (iii) is biconcave in shape (iv) would be relatively low in a haemophilic condition (v) is produced in the bone marrow: (vi) is a thrombocyte; (vii) is nucleated.
(c) Mention three chemical substances transported by the blood component named in 1(b)(i).
(d) List four diseases associated with blood.
(e) Explain briefly why a disease of the blood could be dangerous.
(a) What is dentition in animals?
(b) Describe briefly the generalised structure of a tooth in animals.
(c) List three food substances that plants manufacture from glucose.
(d) Make a diagram, 6 cm to 8 cm long of an experimental set-up to show that oxygen is produced during photosynthesis.
(a) Complete the table below by placing each of the following organisms under the appropriate heading: Algae, Bacteria, Dog, Water lettuce, Tadpole, Cat, Lemna, Waterleaf, Mucor, Mushroom
(b)(i) Name four products of decomposition (ii) Mention three roles of decomposers on a refuse dump
(c) List three materials found in a refuse dump which would not be affected by the action of decomposers.