Question

3. Adult urochordates lack notochord and nerve cord but they are included under Phylum Chordata because -
1) Their larvae possess notochord from its anterior to posterior end
2) They posses nerve cord and notochord in the larval tail
3) They are Enterocoelomates and undergoes progressive metamorphosis
4) Their larvae posses notochord, nerve cord, paired pharyngeal gill slits and post anal tail​

Answer 1

Urochordates

Explanation:

• If we talk about Urochordates they are indeed included under Chordata phylum because they do show typical chordate characteristics but not in adult form whereas in its larval form.
• Thus it larval form has a notochord, nerve cord, paired pharyngeal gill slits and post-anal tail which are pre-requisites of a phylum to include under Chordata thus it is categorised as chordate.
• Now, from the given options,  Option 1 and 2 is right but incomplete, therefore the most appropriate option will be option 3