B. cnidarian
C. arthropod
D. roundworm
The correct answer is option D, Round worm
Roundworm belongs to the phylum Nematodes and some common characteristics of Nematodes are – they are small, slender , un-segmented, smooth and shiny. Roundworm has a round body just like a spiny –headed worm which do not have segments . Also they possess a body cavity known as pseudocoel in which the internal body organs lie and the body cavity is not lined with mesodermal cells.
Answer:
A. Species have changed over time
Explanation:
1. mRNA (messenger RNA): it provides the template for protein synthesis during translation.
2. tRNA (transfer RNA): it brings amino acids and reads the genetic code during translation.
3. rRNA (ribosomal RNA): it plays a structural and catalytic role during translation.