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The amount of blood flowing through a certain parts in the mammalian body at different activity levels was measured and results tabulated as shown in the table below.

(a) Account for:
(i) The high blood flow through cardiac and skeletal muscles during strenuous exercises.
(ii) The results obtained for the alimentary canal at rest.
(b) Name two wastes materials excreted by both the skin and the kidney.

Answer Text:
a) i)- During strenuous exercises heart beat increases to supply more blood
to contracting skeletal muscles which require more energy , therefore a lot of glucose/ amino acid molecules of ATP is needed for more contraction. Also muscles contraction and relaxation increases. Waste material like #CO_2# and lactic acid produced need to be carried away from muscles for elimination.
ii)- At rest more blood passes through alimentary canal at rest to supply more oxygen and nutrients required to support activities of digestive track such as secretion hormones and enzymes, digestion and absorption of digested foods and to eliminate wastes.
b)- Water
- Salts
- urea