Answer:
The semilunar valves prevent backflow of blood into the ventricles.
Explanation:
The semilunar valves are valves found at the junction between the left ventricle and the aorta and also between the right ventricle and the pulmonary artery. They are cup-like in shape and prevent blood from flowing back into the ventricles which are the pumping chambers.
There are two types of semilunar valves. The aortic semilunar valves and the pulmonary semilunar valves. They are made up of the endocardial and connective tissue.
The closure of the semilunar valves causes the second heart sound detected on the stethoscope.
Diseases that arise from the semilunar valves are caused by its stenosis which is the narrowing of the valves and regurgitation where the heart valves can no longer hold firm enough to prevent the backflow of blood.
Answer: The carbon that plants need for photosynthesis comes from carbon dioxide, or CO2 that's present in our atmosphere.
Explanation: Carbon dioxide is released into the air by organisms, such as animals that undergo cellular respiration. In other words, we breathe out CO2 as a waste product.
Answer:
mouse thats immune to poison
Answer:
b. 8P+ , 10no , 8e-
Explanation:
An isotope is a form of a chemical element whose atomic nucleus of an element contains a specific number of neutrons and protons. For example, the nucleus of a carbon atom contains 6 neutrons(no) and 6 protons(P+) and similarly in the nucleus of oxygen contains 8 neutrons and 8 protons . The number of neutron can varies in the nucleus of that element. Variation in neutrons form isotopes of the element. In nature, oxygen has three stable isotopes, ¹⁶O, ¹⁷O, and ¹⁸O, but ¹⁶O most abundant. The ¹⁸O isotope of oxygen contains 8 protons(P+), 8 electrons(e-) and 10 neutrons(no) instead of normal 8 neutrons.