When a blood vessel is cut/injured platelets/thrombocytes/damaged tissue/wound is exposed to the air; they release thrombokinase/thromboplastin ; an enzyme that activates the conversion of prothrombin; to thrombin; in the presence of calcium ions; vitamin KJ phylloquinone ; is needed for the formation of prothrombin; Thrombin converts (soluble blood protein) fibrinogen ; into (the fibrous form) fibrin; which forms a mesh / network across the wound; The clot so formed prevents excessive bleeding; and entry of disease agents/pathogens/micro-organisms/microbes.
adhixbelly answered the question on September 20, 2017 at 13:37
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Using a microscope, a student counted 55 cells across a field of view whose diameter was 6000µm. Calculate the average length of the cells....
(Solved)
Using a microscope, a student counted 55 cells across a field of view whose diameter was 6000µm. Calculate the average length of the cells
Date posted:
September 20, 2017
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Answers (1)
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(a) State two roles of mucus in the stomach. (b) Explain how age determines a person's energy requirements.
(Solved)
(a) State two roles of mucus in the stomach.
(b) Explain how age determines a person's energy requirements.
Date posted:
September 20, 2017
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Answers (1)
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How does excretion take place in plants?Describe the role of the human skin in homeostasis.
(Solved)
How does excretion take place in plants?Describe the role of the human skin in homeostasis.
Date posted:
September 20, 2017
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Answers (1)
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(i)How is sex determined in man? (ii) Differentiate between sickle cell anemia and sickle cell trait. (iii) Explain why people with sickle cell trait have an adaptive survival advantage...
(Solved)
(i)How is sex determined in man?
(ii) Differentiate between sickle cell anemia and sickle cell trait.
(iii) Explain why people with sickle cell trait have an adaptive survival advantage...
Date posted:
September 20, 2017
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Answers (1)
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(a) Describe the mechanism of gaseous exchange in plants through the lenticels. (b) Explain each of the following:the tracheoles lack spiral bands of chitin;the floor of the mouth...
(Solved)
(a) Describe the mechanism of gaseous exchange in plants through the lenticels. (b) Explain each of the following:the tracheoles lack spiral bands of chitin;the floor of the mouth...
Date posted:
September 20, 2017
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Answers (1)
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(a) State four characteristics of fruits dispersed by animals. (b) State two roles of each of the following hormones in menstruation:l (i) luteinising hormone (ii) oestrogen.
(Solved)
(a) State four characteristics of fruits dispersed by animals. (b) State two roles of each of the following hormones in menstruation: (i) luteinising hormone (ii) oestrogen.
Date posted:
September 20, 2017
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Answers (1)
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Why is a burning charcoal stove in a poorly ventilated room likely to cause death of the inhabitants?
(Solved)
Why is a burning charcoal stove in a poorly ventilated room likely to cause death of the inhabitants?
Date posted:
September 20, 2017
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Answers (1)
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Name three types of transpiration
(Solved)
Name three types of transpiration
Date posted:
September 19, 2017
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Answers (1)
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a)What is meant by seed dormancy? (b)state three causes of seed dormancy?
(Solved)
a)What is meant by seed dormancy? (b)state three causes of seed dormancy?
Date posted:
September 19, 2017
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Answers (1)
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Outline types staining process
(Solved)
Outline types staining process
Date posted:
September 18, 2017
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Answers (1)
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What is Biology?
(Solved)
What is Biology?
Date posted:
September 18, 2017
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Answers (1)
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What is a gene?
(Solved)
What is a gene?
Date posted:
September 18, 2017
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Answers (1)
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What type of membrane is the cell membrane in terms of permeability?
(Solved)
What type of membrane is the cell membrane in terms of permeability?
Date posted:
September 18, 2017
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Answers (1)
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What is the name of an RNA sequence that codifies one amino acid?
(Solved)
What is the name of an RNA sequence that codifies one amino acid?
Date posted:
September 18, 2017
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Answers (1)
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Where does respiration take place in a cell?
(Solved)
Where does respiration take place in a cell?
Date posted:
September 18, 2017
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State the adaptations of plants which enable them to reduce water loss
(Solved)
State the adaptations of plants which enable them to reduce water loss
Date posted:
September 18, 2017
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Answers (1)
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State the structural differences between xylem vessels and sieve tubes
(Solved)
State the structural differences between xylem vessels and sieve tubes
Date posted:
September 18, 2017
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Answers (1)
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Explain the environmental factors that affect rate of transpiration in plants
(Solved)
Explain the environmental factors that affect rate of transpiration in plants
Date posted:
September 18, 2017
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Answers (1)
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Explain the structural factors that affect the rate of transpiration in plants
(Solved)
Explain the structural factors that affect the rate of transpiration in plants
Date posted:
September 18, 2017
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Answers (1)
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Explain the uptake of mineral salts by plants
(Solved)
Explain the uptake of mineral salts by plants
Date posted:
September 18, 2017
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Answers (1)