Fats and oils added to baked goods help tenderize, add flavor and moisture.
no
Yes, you can. Olive oil will affect the flavor of the muffins, so would be most successful in savory muffins - corn, cheese or spicy muffins with sage and thyme, or chopped onion and celery. For sweet muffins, I recommend canola oil because it has a neutral taste. But olive oil works for sweet muffins, too. It's used in several types of Italian cakes.
It depends on what type of muffins you're baking. Extra virgin olive oil is the most flavorful of olive oils, being the product of the first pressing of the olives; therefore, it has a very distinct, olive-like flavor. So, if you're making sweet muffins, it would be better to use canola or vegetable oil. Those oils don't really have much flavor, and won't affect the taste. But, if you're making muffins that are heartier (using bran or granola or nuts, and very little, if any, sugar/fruit), then olive oil may be an interesting flavor to add.
You can use alternatives like vegetable oil, applesauce, or Greek yogurt as substitutes for butter in muffins.
you use an egg to make them stick
No. but you could try chutney or jam. If you mean the other way round, you can use applesauce to replace oil when making muffins and cakes to reduce the fat content.
eggs make the muffins coagulate
For making popcorn, you should use about 2-3 tablespoons of oil per 1/2 cup of popcorn kernels.
Yes, you can use canola oil instead of vegetable oil when making brownies.
Conventional ovens and some toaster ovens can be used to bake muffins. You cannot use a microwave oven to bake regular muffins.
When making a roux, especially a dark roux it is best to use oil instead of butter.
no