Well , the humans have a closed double circulatory system as the blood passes by the heart twice per one cycle and doesn't leave the blood vessels like in insects.
》Pulmonary circulation : Blood is circulated to the lungs where it is oxygenated.
》Systemic circulation : Blood is circulated through all the other parts of the body where it unloads oxygen.
Oxygenated blood coming from the lungs enters the heart through the pulmonary vein which takes blood to the first chamber it meets ; the Left atrium. Left atrium pumps blood to the second chamber , which is left ventricle and during this time , the semi lunar valves are closed to prevent back flow of blood and the bicuspid valve will be open . Now , the left ventricle is filled with oxygenated blood so it will pump this blood to the whole body via the largest artery which is Aorta.
Oxygenated blood will unload oxygen to cells in need of it and will return back now to the heart as deoxygenated . This deoxygenated blood will enter the heart through superior and inferior vena cava which will take the blood to the third chamber , right atrium . Right atrium will pump blood to right ventricle so the semi lunar valves will be closed during this time and the tricuspid will remain open. Now that the fourth chamber is filled with deoxygenated blood , it will pump this blood through pulmonary artery when the semi lunar valves opens , to the lungs again to be oxygenated once more.
Notice that you have to know exactly the position of the valves that I have mentioned in the heart so that you could understand the blood flow better. You can refer to any heart labelled diagrams in your textbook or the internet.
Chimneys are typically vertical, or as near as possible to vertical, to ensure that the gases flow smoothly, drawing air into the combustion in what is known as the stack, or chimney effect.
Yes they should be viewed as nonliving. Because viroids are just like viruses without protein coats. They are similar to viruses excepte the protein coat. And prions are like malfunctioned proteins. They cause diseases too but they are non-living too. Because they too, don't have any metabolics reactions.
The answer would be osteoporosis
Osteoporosis comes from word osteo- which mean bones and -porosis which means "pore". The term is used to describe a decrease in bone density which makes them seems like having multiple pores. It is found more in the old patient because the bone formation is decreased.
Answer:
Open-Mindedness means capable of accepting new and different ideas, while Skepticism means having an attitude of doubt.
Explanation;
Scientific Attitudes includes; curiosity, Honesty, Open Mindedness and Skepticism, Creativity.
Curiosity is successful scientists are eager to learn more about the topics they study. Good scientists always report their observations and results truthfully. This is especially important when a scientist's results go against previous ideas or predictions.
Open-Mindedness involves being capable of accepting new and different ideas while Skepticism is having an attitude of doubt and Creativity involves coming up with inventive ways to solve problems or produce new things.
