Answer - Cyanobacteria aka Algae that contributed in creating O2 for the atmosphere as a byproduct thru Photosynthetic.
Reason - Of course Algae make up mainly the whole world in waters and they do photosynthesis to give off oxygen in the atmosphere.
Threats to Native Wildlife. Invasive species cause harm to wildlife in many ways. When a new and aggressive species is introduced into an ecosystem, it may not have any natural predators or controls. ... Invasive species can also alter the abundance or diversity of species that are important habitat for native wildlife.
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Geiger-Muller tube is instruments requires you test three times the background of the work area.
<u>Explanation</u>:
These detectors are gas filled detectors and hence requires time for responding to the value. This time is taken because during this period it collects the electric charges and features of the electric circuit. It also gets stabilized during this period. This device has thumb rule i.e one must wait or hold for at the least 3 times the time constant before getting the precise and accurate reading. The time constant order is 10 seconds for the ionization chamber but for the Geiger counter it can vary from seconds to greater than 20 seconds
