During which phase of the cell cycle do chromatids form?

ya the other dude is right

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.

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.

the answer you are looking for is the united states forest service.

hope this !