1. nervous systems are required by animals to respond to stimuli and have complex senses such as taste, touch, sight, smell, or sound. these are carried by nerves to and from the brain and spinal cord. of all major animal phyla, which does not have nerves?

a. annelids
b. porifera
c. chordata
d. cnidarians

B. Porifera. Porifera (sponges) is the only major phyla without nerves

Of all the major phyla the one that does not have a proper nervous system is the Porifera.

Option B

Explanation:

Any organism requires a nervous system to communicate between the activity center that is the brain. The nerves serve as communication vehicles between the brain and other parts of the body .

The phylum porifera majorly contains the sponges which do not have any nerve or brain cells . Their major communication between cell to cell is the circulation of water and the ejection of waste that occurs from the inside to the outside.

is in the form atp or adenosine triphosphate

the tricuspid valve is present between right atrium and right ventricle