Some samples are transparent, or very difficult to see, therefore, they are stained in order to be seen more clearly and easier to work with.
During eye surgery, the clear layer of the eye is stained to be easily extracted, if it was clear then the surgeon might cut the eye instead of just the layer.
Hope this helps, u might want to search online for more info.
Ammonoids are good as index fossils because of the following characteristics;
<span>1.
</span>Their abundance and vast distribution across most shallow
marine waters during the periods
<span>2.
</span>They have easily recognizable
features, such as shells and the highly crenulated and complex suture, that are well preserved in rocks
<span>3.
</span>Their rapid
evolution that can assist determine changes and variations in the then environment
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Answer:
Equal amounts of DNA contain equal proportions of nitrogenous bases.
Explanation:
According to Chargaff's rule, the nitrogenous base pairs (Purines and pyrimidines) have an equal ratio (1:1) in the DNA of all the organisms. More precisely, the amount of adenine is equal to thymine and the amount of guanine is equal to cytosine in the DNA of all the organism. A-T base pair has two H-bonds while G-C base pair has three H-bonds.
It is the first option. Atmospheric nitrogen is very stable so there fore hard to react with. But bacteria contain molecules that can break the bond of nitrogen.