Which is the main advatage of having a coelom body cavity?
a. being able to perform extracellular digestion
b. space for complex organ systems
c. having an open circulatory system
d. having a closed circulatory system

b. Space for complex organ systems

Explanation:

Coelom can be defined as a fluid-filled body cavity with mesoderm lining, one of the germ leaflets.  In triblastic animals, there may or may not be coelom. Those who have the cavity have the advantage of using this cavity to store complex internal organs (viscera). When there is no coelom, animals are said to be aceloma, like the flat-body worms - the flatworms.

This cavity is formed during embryonic development and is related to several important functions, such as excreta elimination, temporary gamete deposition, distribution of substances throughout the body, accommodation of internal organs and, in some animals, it also functions as a support.

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.