Why was an algae cell included along with the plant and animal cells?

In particular, organelles called chloroplasts allow plants to capture the energy of the Sun in energy-rich molecules; cell walls allow plants to have rigid structures as varied as wood trunks and supple leaves; and vacuoles allow plant cells to change size.

from the original order (top to bottom) the new order will go

1 (founder)

4 (hawk)

2 (mutate)

3 (next generation)

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.