Q.dwarf key lime tree
Bought the dwarf key lime tree last August. It was a 2 to 3 year old and doing very well. It started blooming last November. The flowers open up and fall off a couple of days. it is still blooming, but no fruit yet! What should I do?

Don't worry, it is common for young limes and other citrus to lose their flowers during the first few years. When they mature, they will start setting fruit, but they will still naturally lose the majority of their flowers (they produce more than they need).
https://www.gardeningknowhow.com/edible/fruits/lime/is-lime-fruit-and-lime-blossoms-falling-off-tree-normal.htm
Also, if you're growing indoors or if there are few pollinators in your area, you may need to hand-pollinate to increase yield:
https://www.gardeningknowhow.com/edible/fruits/lime/hand-pollinating-limes.htm