Question

Circulatory system in Cephalochordates is:
a) Well developed, closed, with a heart &
lacks a respiratory pigment
b) Poorly developed, open, with a heart
& lacks a respiratory pigment
Well developed, open, with a heart
and lacks a respiratory pigment
d) Well developed, closed, without a heart
and lacks a respiratory pigment​

Answer 1

Answer:

d) Well developed, closed, without a heart  and lacks a respiratory pigment​

Explanation:

Cephalochordates have a closed circulatory system (the blood is enclosed in blood vessels) but lack a central pump (heart). Instead, the blood is propelled by pulsation (rhythmic contraction and relaxation) of several blood vessels. ... The central nervous system of the cephalochordates is very simple.