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.
A. Hormones
secreted directly into the blood
Answer:
Chromosomes at the conclusion of Meiosis I - 
Double-helical molecules of DNA at the conclusion of Meiosis I - same as that of parent cells
Explanation:
Given
Number of chromosomes in the diploid cells of Aliens from the planet Zorg 
In the Meiosis I cell division , a cell divides to produce two diploid cells with exactly the same amount of DNA as that of original parent cell.
However, the number of chromosomes is reduced to by half at the end of meiosis I
After Meiosis II, four haploid cells are produces with half the amount of DNA as that of original parent cell
Thus,
Chromosomes at the conclusion of Meiosis I - 
Double-helical molecules of DNA at the conclusion of Meiosis I - same as that of parent cells