Will give brainliest and points!
which organism exhibits a dorsal nerve chord at some stage of its development?
a snail
a grasshopper
a jellyfish
a lancelet

which group exhibits gill slits at some stage of development?

all echinoderms

all chordates

all mollusks

all cnidarians

A. Lancelet

B. All chordates

Explanation:

A. Dorsal nerve chord is the only unique feature among all members of phylum chordata (mainly found in subphylum Vertebrata). In the given list, only lacelet is the Chordate whereas snail belongs to phylum Mollusca, grasshopper belongs to Arthropda, and jellyfish belongs to Cnidaria. Dorsal nerve cord runs along the length of organism's body.

B. Gill slits are opening structures to gills through which water passes from pharynx/throat to exterior. Their main purpose is to help filter the food particles available in surrounding water. Although they are typical for amphibians and fishes, chordates also possess gill slits at embryonic stages.

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