During a dissection of a sheep heart, a student observes a flap between the right atrium and right ventricle. The flap closes as the right ventricle contracts.
Which movement of blood is prevented when the flap closes?
From the right atrium into the vena cava
From the right ventricle into the right atrium
From the right ventricle into the pulmonary artery
From the pulmonary artery into the right ventricle
114 exam-style questions on OCR GCSE Biology 2.2 The challenges of size, covering 2.2.1 Exchange surfaces and surface area : volume ratio, 2.2.2 Substances transported in organisms, 2.2.3 The human circulatory system, 2.2.4 The heart and blood vessels, 2.2.5 Red blood cells and plasma, 2.2.6 Uptake of water and mineral ions by plants, 2.2.7 Transpiration and translocation, 2.2.8 Xylem and phloem, 2.2.9 Environmental factors and water uptake, and 2.2.10 Using a potometer. Each one has a worked solution and a mark scheme showing where the marks go.