Answer:
They used relative dating to divide Earth's past in several chunks of time when similar organisms were on Earth. Later, scientists used absolute dating to determine the actual number of years ago that events happened. The geologic time scale is divided into eons, eras, periods, and epochs.
Explanation:
Answer:
Experimental design means planning a set of procedures to investigate a relationship between variables, or experimental design refers to how participants are allocated to the different groups in an experiment. The types of design include repeated-measures, independent-groups, and matched pairs design.
Annotated bibliography provides specific information about each source you've used. As a researcher you have become an expert on your topic: you have the ability to explain the content of your sources, assess the usefulness, and share this information with others who may be less familiar with them.
Annotated bibliography is a list of citations to books, articles and documents.
Good environmental science experiments are;
1.Water science fair projects.
2. Air quality Science fair projects
3. Climate change Science fair projects
4. Solid waste recycling Science fair projects.
Explanation:
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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.
The have amplitude will grow, it will be bigger
