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hvvvvOxford Cambridge and RSA
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wewewThursday 22 May 2025 – Morning
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sfdddgdAS Level Biology B (Advancing Biology)
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dfdgggffffrH022/02 Biology in depth
AS-Level OCR 2025 Biology B (Advancing
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, 2
1
(a) The mammalian circulatory system is described as a closed double circulatory system.
(i) Explain what is meant by a closed circulatory system.
..........................................................................................................................................................
...................................................................................................................................................................... [1]
(ii) The diagram below shows the circulatory system of a frog.
Capillaries in the lungs and skin
right left
side side
Capillaries in the muscles
Blood leaving the heart of a frog is less oxygenated than blood leaving the heart of a mammal.
Explain why blood leaving the heart of a frog is less oxygenated than blood leaving the heart of a
mammal.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
...................................................................................................................................................................... [2]
© OCR 2025
, 3
(b) The image below shows a section through the wall of an artery.
X Y
×500
Calculate the actual width of the artery wall between points X and Y.
Give your answer to the nearest whole number.
Actual width =............................................................ μm [2]
© OCR 2025 Turn over
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hrr dh
hvvvvOxford Cambridge and RSA
Hfjdfefdfbyebh jhjhssjkkc dc hc
eucscshcsjcsihsduhhhhhhhhhhhhdcshhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
wewewThursday 22 May 2025 – Morning
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sfdddgdAS Level Biology B (Advancing Biology)
hggggggggggggggggggggggggggggggggggggggggggggggggggg
rtrtrtrtrrtrtrHghfgfffffffffh
dfdgggffffrH022/02 Biology in depth
AS-Level OCR 2025 Biology B (Advancing
jhhhhgggggggggggggggggggggggggggggggggggggghhhhhhhhhhhhhhhhhhhhhhhhhhhh
hhhhhhhhhhhhhhhhhhhhhhh Biology) Paper 2
jhjhhjhjhjTime allowed: 1 hour 30 minutes
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sssssssssssee
, 2
1
(a) The mammalian circulatory system is described as a closed double circulatory system.
(i) Explain what is meant by a closed circulatory system.
..........................................................................................................................................................
...................................................................................................................................................................... [1]
(ii) The diagram below shows the circulatory system of a frog.
Capillaries in the lungs and skin
right left
side side
Capillaries in the muscles
Blood leaving the heart of a frog is less oxygenated than blood leaving the heart of a mammal.
Explain why blood leaving the heart of a frog is less oxygenated than blood leaving the heart of a
mammal.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
...................................................................................................................................................................... [2]
© OCR 2025
, 3
(b) The image below shows a section through the wall of an artery.
X Y
×500
Calculate the actual width of the artery wall between points X and Y.
Give your answer to the nearest whole number.
Actual width =............................................................ μm [2]
© OCR 2025 Turn over
