Why do you think the whitefish blastula was chosen rather than a sample of adult tissue to view on a slide

Explanation:

Blastula is an early stage of embryo development, it is the continuation of t morula which is when the zygote is moved to uterus.

Cells in blastula are actively dividing as formation is still taken place, and are used because this dividing cells are very large and can be easily seen. The chromosomes of Blastula are also more visible than human chromosomes hence necessitates it uses.

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.