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BIOL 251 UNIT Test 1 quizes and answers 100% correct BIOL 251 UNIT Test 1 quizes and answers 100% correct BIOL 251 UNIT Test 1 quizes and answers 100% correct BIOL 251 UNIT Test 1 quizes and answers 100% correct BIOL 251 UNIT Test 1 quizes and answers 100% correct BIOL 251 UNIT Test 1 quizes and answers 100% correct BIOL 251 UNIT Test 1 quizes and answers 100% correct BIOL 251 UNIT Test 1 quizes and answers 100% correct BIOL 251 UNIT Test 1 quizes and answers 100% correct BIOL 251 UNIT ...

Study guide (Science) 100% Verified Science - answerA way of learning about the natural world. Observation - answerAn investigation based on inferences. Inference - answerA guess about an observation. law - answerDescription of how things happen in nature. Theory - answerAn explanation based on evidence, of why things happen. Hypothesis - answerA testable prediction that attempts to answer a question. Independent variable - answerWhat is being purposefully being changed. Dependent variab...

Two students are doing an experiment to investigate reaction times. The diagram shows their experiment. Tester Participant (a) The statements outline the method used. They are not in the correct order. (i) Write the letters in the boxes to show the correct order of the statements. The first one has been done for you. E [2] (ii) Suggest two improvements to the method that would ensure that the measurements taken were valid. Improvement 1 .................................................

The combustion of fossil fuels for energy produces harmful substances. (a) (i) Draw lines to connect each harmful substance with the description of its major source. Harmful substance Major source [2] (ii) Explain one problem caused by increased amounts of sulfur dioxide in the atmosphere. ........................................................................................................................................... ...............................................................

A doctor uses a light microscope to look at the chromosomes in human body cells. (a) The microscope is shown in the diagram. Fine focus Part A Part B Part C Coarse focus Mirror (i) Draw lines to connect each part of the microscope with its correct name. Part Name [1] (ii) The doctor uses steps A to D to look at the cells on a slide. The steps are not in the correct order. A Turn the coarse focus until the image is as clear as possible. B Turn the fine focus until the image is as cl...

2 © OCR 2023 Stomach acid Clots the blood to prevent pathogens from entering cuts Skin Produces antibodies, or ingests and digests pathogens Platelet Barrier that prevents pathogens from entering the body White blood cell Can kill pathogens and stop them from reproducing 1 Pathogens can cause diseases in humans. Draw lines to connect each defence mechanism with the explanation of how it functions. Defence mechanism Explanation [3] 3 © OCR 2023 Turn over 2 (a) The plant geno...

2 © OCR 2023 ring ring 1 Ling has a torch with a filament lamp. (a) What is the correct circuit symbol for a filament lamp? Put a around the correct option. [1] (b) The torch is not working. Ling makes this circuit to test components. Ammeter Crocodile clip A B Crocodile clip Battery Complete the sentences to explain how the circuit works. Put a around each correct option. A component is connected to A and B using the ammeter / battery / crocodile clips. If the ammeter measure...

2 © OCR 2023 1 The diagram shows part of Mendeleev’s Periodic Table. B 11 C 12 N 14 O 16 F 19 Al 27 Si 28 P 31 S 32 Cl 35.5 As 75 Se 79 Br 80 In 115 Sn 119 Sb 122 Te 128 I 127 (a) Give the symbols of the two elements shown in the diagram which are not in order of atomic mass. ........................................................... and ........................................................... [1] (b) Mendeleev left gaps for elements that had not ...

2 © OCR 2023 Chemical Bacteria in the gut compete against pathogens Microbial Skin stops pathogens entering the body Physical Stomach acid destroys pathogens 1 Some bacteria are pathogens that cause diseases. (a) Our blood contains white blood cells. They help protect us against pathogens. (i) Write down the name of the organ that pumps the blood around our body. .............................................................................................................................