Answer:
(4) tissues
Explanation:
There are three circles the innermost circle indicated the cells middle circle is the tissues and the outermost circle indicated the organs. Multicellular organisms are made up of thousands of different types of cells .Different cells constitute together forma a tissues and different tissues form a organ and different organs together form an organ system. Hence the X labeled circle denotes the tissues.
In amino acids, the carboxyl group acts as an acid.
Answer: Option B
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Explanation:
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The molecular formula of the carboxyl group is -COOH. It is composed of one carbon atom bonded with oxygen atom and hydroxyl group.
During ionization process, it leads to the formation of two ions namely a positive ion called
, whereas a negative ion called
. Due to the formation of
ions, which is nothing but a proton, the carboxyl group present in the amino acid act as an acid.
Mars..........................