First answer is , as the work of ventricle is to push blood to he whole body , so it has to be strong or it can not pump blood to head to the toe !
as in frog (an amphibian ) it has only three chambers as two artia and one ventricle, so the oxygenated blood from left artia and deoxygenated blood from right , combines and thus partial oxygenated blood is circulated !
I think the answer to this is abyssal plane
<h2>Answer:</h2>
Bacteria provide genetic engineers with <u>_vector_ </u>and <u>_host_.</u>
<h3>Explanation:</h3>
Vector are vehicles or carriers which are used to carry the gene of interest. They are usually plasmids which are bacterial circular genome which can replicate independently.
Hence bacterial plasmids are used for the insertion of gene of interest and its transfer to the host cell.
As plasmids is taken from the bacteria, so mostly bacteria is used as the host for the gene of interest.