The first, second, and fourth statements are correct.
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The right atrium receives blood returning from others parts of the body through the superior vena cava and the inferior vena cava.
Explanation:
The pathway of circulation begins in the right atrium which receives the carbon dioxide-rich deoxygenated blood returning through the systemic circulation.
The deoxygenated blood from regions superior to the heart, i.e., the head, neck, shoulder areas are collected through the superior vena cava and that from the parts inferior or lower to the heart like visceral organs, extremities, trunk, hip etc are brought through the inferior vena cava.
Both these venous systems (superior and inferior) fill the right atrium.
The right atrium then pumps the deoxygenated blood to the right ventricle via the tricuspid valve.
The right atrium is filled with blood during diastole.
D) Yes, the need to conserve copper must be balanced with use.
an egg cell has a haploid nucleus so it has half the number of dna because it fuses with a sperm cell to have the full amount of dna.
an egg cell has 23 chromosomes and a sperm cell has 23 chromosomes.
they both have half the amount of dna to form a zygote