What is a characteristic of all chordates at some point during their life cycle?

they possess notochord,dorsal tubular nerve cord , pharyngeal pouches

Explanation:chordates are animals which possess the notochord.examples are humans,birds,fishes etc

At a time in the life cycle,a chordates possesses a stiff,dorsal rod which is supporting in nature (the notochord).

They also possesses a tail that extends from behind the anus.

They possess a hollow nerve cord.

They possess gills slit.

These characteristics are present developing embryo and may disappear as the embryo matures.

In humans,the notochord is replaced by the spinal column of the vertebrate.

allowed for the prediction of the properties of missing elements.