Which animals' ancestors were related to the earliest chordates?" a Echinoderms

b Mollusks

c Arthropods

d Cnidarians​

The earliest chordates were all marine animals like tunicates and lancelets.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.

those characteristics are cellular organization, reproduction, metabolism, homeostasis, heredity, response to stimuli, growth and development, and adaptation through evolution. some things, such as a virus, demonstrate only a few of these characteristics and are, therefore, not alive