Answer:
It is called pen and it is located at the dorsal side
Explanation:
Squid belongs to the class Cephalopoda, subclass Coleoidea which is characterized by internal shell (unlike subclass Nautiloidea in which shell is located externally).
The shell of the squid (the pen) in very reduced and small, formed from chitin and located at the dorsal side. The pen provides attachment for muscles and it gives the squid stiffness.
Most likely, this internal shell evolved from the external shell, because it is believed the ancestral of the organisms from the Coleoidea was probably nautiloid-like.
"Pheromones" is the one among the following choices given in the question that these messengers are called. The correct option among all the options that are given in the question is the second option or option "B". I hope the answer has actually come to your expected help.
The answer is C, sunlight
Answer:
By difference in there ribosomal RNA sequence
Explanation:
Both bacteria and archaea lack membrane-bound nucleus and earlier both are considered in the same categories. Carl Woese was the scientist who discovered that bacteria and archaea are not similar.
Carl Woese and his lab members checked the ribosomal RNA in some archaeans and concluded that the archaeans are more closely related to eukaryotes than bacteria. After the study on archean Carl Woese classified the prokaryotes into two domains i.e., bacteria and archaea.
Therefore by difference in the ribosomal RNA sequence archaeons first distinguished from other prokaryotes.
the answer you put is right
