False. Strontium 90 has a half life of only 30 years, and as millions of years pass, about the time fossils have been around, most if not all of any strontium would have decayed.
Answer:
Electron microscope is a device which is used to see microscopic objects using electon. In this tyoe of microscope electron is thrown on an object whose image is formed on the screen. It resolution power is 10,000X. If the internal structure of an object is to be observed then SEM is used, however for three dimensional structure, TEM is used.
Answer :
The animals are categorized into 2 groups - eukaryotes and prokaryotes. The microbes like bacteria are coming under prokaryotes. They are unicellular organisms and without a true nucleus.
Viruses are the connecting link between the living and non - living. They are smaller than bacteria. The microbes less than 100 micrometer can't be seen by the naked eye. They can only visible under a microscope.
Viruses like polio, flu virus sizes are 10nm. But some of the viruses are also less than 10nm. The size of bacteria is 1 micrometer. The viruses are 10 times smaller than the bacteria.
The eukaryotic organisms are more advanced and multicellular. Their cell size is larger than bacteria and viruses. The red blood cells under the light microscope are 8 micrometers. The typical animal cells like sperm are 60 micrometers and a skin cell is 30 micrometers. The plant cell for example pollen is 90 micrometers.
The eukaryotic cells sizes are more than prokaryotes like bacteria.
