Systemic heart refers to
- the heart that contracts under stimulation from nervous system
- left auricle and left ventricle in higher vertebrates
- entire heart in lower vertebrates
- the two ventricles together in humans.
Answer
(3) entire heart in lower vertebrates
Solution
As per NCERT, fishes have a 2-chambered heart and show single circulation: the heart receives blood only from the body and pumps it out once, through the gills, to the body.
⇒ In lower vertebrates the whole heart works for a single (systemic) circuit; there is no separate pulmonary heart.
⇒ In birds and mammals (double circulation) the heart is divided into a right (pulmonary) side and a left (systemic) side.
∴ In lower vertebrates the entire heart is the systemic heart.
Answer: (3)