It is called the esophagus
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The answer is D. An irritant that because embedded in the mantle
The right answer is A.
Insecticides are active substances or phytosanitary preparations with the property of killing insects, their larvae and / or their eggs. They are part of the family of pesticides, themselves included in the family of biocides, both of which are regulated in Europe by specific directives.
Some pestiids such as organoclorides are broad-spectrum, ie they act on several insects at the same time (whether they are good or bad).
C. the mesosphere is the correct answer