How did the earliest chordates obtain food?
a. They were filter-feeders
b. They were herbivores, consuming photosynthetic algae.
c. They had symbiotic green algae that produced most of their energy.
d. They were predators, catching mostly marine crustaceans.
e. They were decomposers, consuming dead worms and crustaceans.

Option A.

They were filter feeders.

Explanation:

The first chordates appear in the Cambrian period and the fossil record shows it to be around 530 milion years ago. This chordates was found in China and recorded in 1995.

The earliest chordates obtain food by filter feeding. They taking in water through the mouth and filter the feed through gills silts.

Chordates characteristics are;

They have notochord.

They have hollow nerve

this protocol provides a detailed procedure for agarose-based ip to purify and enrich the protein of interest.

i am going to guess that it is co2.