3 questions I have the answer can you explain how to get it

1) During the closing process, which of the following accounts are closed out to the Income Summary account before they are eventually placed into Retained Earnings? the answer is revenue and expense accounts. why

2) If Cost of Goods Sold (COGS) is $675,000, Cost of Goods Available for Sale is $1,400,000, and Purchases are $125,000, Beginning Inventory is _____________ and Ending Inventory is ______________. the answer is $1,275,000 ; $725,000 how can you explain

3) ODea, Inc. has the following inventory data: July 1 Beginning Inventory 20 units at $19 $380 July 7 Purchases 70 units at $20 $1,400 July 22 Purchases 10 units at $22 $220 100 $2,000 A physical count of merchandise inventory on July 31 revealed that there are 32 units on hand. Using the FIFO inventory method, what is the amount of Cost of Goods Sold for July? the answer is $1340. How?