How is relative-age dating used to determine the ages of fossils? -by observing the formation of sedimentary rocks -by using radioactive isotopes -by estimating the number of fossils in a particular region -by the formation of igneous rocks -by identifying the way the fossils were formed

The image shows ekgs of a person with normal heart waves and of a person having tachycardia. based on this image, what kind of condition is tachycardia? a. the heart beats abnormally fast. b. the heart beats abnormally slow. c. the right atrium of the heart stops working. d. the left ventricle pumps less blood to the aorta.

Classify the structures as homologous or analogous, depending on their structure and function.

This is a typical grassland food web. it is also a small picture of an important cycle on earth: the carbon cycle. describe how the carbon gets into this food web. a) bacteria and fungi, the decomposers, recycle carbon from dead organisms. b) carbon is found in the grass and is passed from one level to the next in this food web. eliminate c) all living things give off carbon dioxide as a by-product of respiration and it is released into the atmosphere. d) plants use carbon dioxide as a reactant in photosynthesis, to make usable chemical energy in the form of a sugar.