(a) Write a short note on the importance of the presence of an effective transport system in mammals.
(b) State eight functions of blood in mammals.
(c) List four materials transported in the bodies of flowering plants.
Explanation
(a) The importance of transport systems in mammals is as follows:
(i) The primary purpose of transport systems is to move materials throughout the body of the organism
(ii) Mammals have various substances/materials for specific functions located in different parts/organs of the body; For example, oxygen is present in the lung while digested food is located in the alimentary canal
(iii) Through transport systems metabolic waste products/excretory products are eliminated/removed via the kidney/lung/skin
(iv) Hormones that are produced by the endocrine glands are made available to far-away cells which they serve
(v). Blood is the main medium of transport; assisted by the lymphatic system/lymph
(vi)Mammals being large and complex organisms have a surface area comparatively smaller than the volume/surface volume ratio is low. Diffusion alone is inefficient
(vii) Therefore there is a need to develop an efficient transport system to cope with this problem.
(b) Functions of blood in mammals:
(i) Blood serves as a transport medium of soluble organic compounds/digested food from the small intestines to various parts of the body where they are stored/assimilated or used; and transported from storage areas where they are used.
(ii) It transports soluble excretory waste materials such as Urea/CO2/to organs of excretion such as kidneys/lungs.
(iii) Transport of hormones / from the glands/corresponding gland/where they are produced to target organs is also facilitated.
(iv) Distribution of excess heat from deeply seated organs to maintain a constant body temperature is equally a function of the blood.
(v) Transport of oxygen from the lungs to all parts of the body/transport of carbon dioxide produced by the tissues to the lungs.
(vi) Defence against disease/foreign bodies through potocytosis.
(vii) When an injury occurs, clotting of blood (by platelets/thrombocytes and fibrinogen) prevents excess loss of blood and also prevents entry of pathogens/germs.
(viii) Immunity is achieved by antibodies and lymphocytes carried by blood.
(ix) Transports water
(x) Transports mineral salts.
(c) The following are materials transported in the bodies of flowering plants:
(i) Latex/secretion/specific secretion
(ii) Water/soil water
(iii) Manufactured food / specific food e.g. glucose, amino acids
(iv) Hormones/auxins
(v) Dissolved mineral salts/specific salts e.g. nitrated, phosphate
(vi) Oxygen
(vii) Carbon dioxide.
(viii) Excretory products