Given the background description of some cooking related query, summarize the question into a title

Q: I have a cake recipe which calls for 1 1/3 cup of vegetable oil. What are the essential properties of vegetable oil in baking? What changes would be expected if I were to substitute peanut or canola oil for the vegetable oil?

A: Substituting oil in baking?
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Q: I use a 10 percent salt solution for my brines. It just seems the easiest. 100 grams of salt per liter of water, but I have read that this is a bit high as most books speak of a 6 percent solution.So I would like to know how long should you brine meat for at this solution? What time with this solution should you brine per kg of meat and does this differ between poultry, fish and red meat?Just a rough estimation would be great as I don't want to over salt the food.

A: How long should meat be brined for in a 10 percent solution?
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Q: When I see tuna steaks, seared rare, on restaurant menus it's almost always Ahi tuna specifically. What's special about Ahi with this preparation method? Does it have different cooking properties from other kinds of tuna steak, like Yellowfin? Or is it an economic matter?I ask partly out of curiosity and partly because I'd like to make this myself, so want to know if I should be preferring Ahi to other tunas that are sometimes at the fish market.

A:
What's special about ahi tuna?
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