In their study of fossils of the extinct arthropod Mollisonia symmetrica, Javier Ortega-Hernández, Sarah Losso and team reported some obvious indications of M. symmetrica's nervous system-for example, the animal's optic nerve. They also saw signs of what might be a syngangtion, a brain-like mass of nerve tissue, in the animal's head.This evidence is exciting because It could help us better. understand how M. symmetrica is related to other arthropods.such as silverfish and giant tiger prawns. 5 A Mark for Review Which choice best describes the function of the underlined portion in the text as a whole? A It explains why the team's finding of a possible syngangtion is exciting. B It gives the definition of the term "synganglion"used earlier in the text. C It states that giant tiger prawns are arthropods but silverfish are not. D It indicates that the team's claims about the M. symmetrica fossils are incorrect.

## Step 1<br />The problem is a reading comprehension question, which requires understanding the context and the role of the underlined portion in the text. The underlined portion is "This evidence is exciting because it could help us better understand how M. symmetrica is related to other arthropods, such as silverfish and giant tiger prawns."<br /><br />## Step 2<br />The underlined portion explains why the team's finding of a possible syngangtion is exciting. It does this by explaining that this evidence could help in understanding the relationship between M. symmetrica and other arthropods.<br /><br />## Step 3<br />The other options do not accurately describe the function of the underlined portion. Option B suggests that the underlined portion provides a definition for "synganglion", but it does not. Option C suggests that the underlined portion states that giant tiger prawns are arthropods but silverfish are not, which is not the case. Option D suggests that the underlined portion indicates that the team's claims about the M. symmetrica fossils are incorrect, which is also not the case.