In diploid species, diploid cells may undergo either mitosis or meiosis. Haploid cells may undergo mitosis (for certain species) but NOT meiosis because

The correct answer would be - Homologous chromosomes cannot pair

Explanation:

Haploid cells are the cells that have single set of chromosome or have the equal number of chromosome as their parent cells. Haploid cells are denoted by the n. Haploid cells are produced by the meiosis and are identical copies of their parent cells,

Haploid cells may undergo mitosis but not meiosis as their are already n number of chromosome and homologous chromosomes are can not pair and meiosis is a reduction division that produces haploid cell from diploid cells.

Thus, the correct answer is - Homologous chromosomes cannot pair

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.

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]