Answer:
This is an controlled experiment because he is only changing the amount of carbon dioxide in the air. Since he is only changing one variable at a time and comparing it to a natural, unaltered tomatoe area, his experiment is controlled.
Explanation:
The definition of a controlled experiment is a test where the person conducting the test only changes one variable at a time in order to isolate the results. An experiment where all subjects involved in the experiment are treated exactly the same except for one deviation is an example of a control experiment.
E. very small atoms
fusion reaction in which two atoms of hydrogen combine together or fuse to form an atom of helium
My answer would be 2:2 for the first one and if they were all girls, assuming none are bald, the ratio would be 4:0. sorry if i’m wrong that’s just how i solved the problem:)
The answer is; Match the grooves along the coastlines of continents
If studied well it is observed that the coastal outlines of continents could fit well into one another just like jig-saw puzzle pieces. This means that the continents were once part of a larger landmass that broke off. The pieces drifted away due to continental drift is driven by convectional currents in the mantle.