Which of the following is a defining characteristic of all Chordates? MCQ with Answer and Explanation

Explanation:
The choroid plexus, located in the ventricles of the brain, is a network of capillaries and ependymal cells that secretes cerebrospinal fluid (CSF). CSF cushions the brain, removes waste, and maintains chemical environment. Meninges are protective coverings, corpus callosum connects hemispheres, pineal secretes melatonin.

Explanation:
The left ventricle pumps blood into the aorta and to the systemic circulation. Its wall is the thickest because it must generate high pressure.

Explanation:
CNS = brain + spinal cord. The peripheral nervous system (PNS) includes cranial and spinal nerves. The autonomic nervous system controls involuntary functions.