Veins take blood back to the heart. which gas would be most abundant in a vein that takes blood from muscle cells in the arm back to the heart?

Plz will mark! the diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

Clues to ecological principles are given in numerous passages of the bible. a bible study of ecology actually opens the doors to better understanding of god's love and concern for the earth. use a concordance to locate bible passages associated with words concerning our stewardship of the earth. you may use a dictionary to find synonyms for these words: dominion replenish subdue judgment stewardship find each of the passages using these words related to principles of ecology. list all passages by quote, book, chapter, and verse under each word. use your own interpretation to rewrite what you think each verse is saying. after your discussion of each of these words, ask one other person to explain his understanding of the word and a related verse without any hints. summarize what he tells you. a concluding paragraph for each of the words should be written noting similarities and differences between your interpretation and that of each person consulted.

According to theories of how life began, how did early organic molecules begin to separate from the outside world? a: specialized enzymes were required b: chains of amino acids created a barrier c: formation of microspheres or vesicles d: rna catalyzed the formation of membranes