Busy Bees is the 51st level in Bloons 2, and the 3rd level in the Rubber Jungle zone.
Solution
There are two zones to target: the Tack Bloon at the very right, and the rest of the zone. Get the throwing of the rightwards Tack Bloon correct first. Then try practice timing top-left Tack Bloon targeting and let the Bee Bloon pop on the same shot, but make sure the timing of the moving Bee Bloon is correct to where the dart trajectory would land. Or do the order of the two target zones the other way round if that's more comfortable. Either way, for the Bee Bloon step, make sure it hits the bottom Tack Bloon and the right bricks and then the Layered Green Bloons.
flowerPop·Billiard Tricks·Trapped in a Box·Pippin·Down the Line·Infiltrate·not very easy·yea boii·pingus 1st one·two hole·Xtreme shooting·Oversized·The Square·Continue Aiming·drop from above·Extra Corner·3 darts your out·Marius XVII·TOUGH STUFF·Tricks·Use The Triforce·Oh Baby·strophik 005·brain challenge2·Wallride V2·strophik 002·beat the bloons·numbur 1·Hate me·loop D loop·what the 3·CHYEA·Watchin Youu·Checkers·Depth Charge·remember me·iced lollie·Trampoline·Acrobatics·be careful·Strategize·Hurry up Fatboy·Beat This·pennpal level 1·MEDIUM 5·care·Got Skill·unFREAKNbelevble·Gotta hit em all·brain challenge
Fun with Bouncy·Noob Pack·Fun Pack·Introduction·Introduction·Introduction·Minesweeper·Pin Practice·Newbie·Angle Bounce·Kyles Baby Pack·Boomerang Skills·Pop Tart·Tribal Attack·Hard·Tools to use·Minesweeper·Vanilla Bloon·Like Christmas·The Best·Koala Fun Pack·White Crane·Freedom·Freedom·Pop Tart·Tools to use·Nightfire·Serene·Boomerangorama·Freedom·Noob Pack·Da Monkey·Extremely Hard·All the Aces·All the Aces·Vanilla Bloon·All the Aces·Major League·Pop Tart·Hit The road·Hit The road·Is this a pack?·Viva La Vida·Ice Ice Baby·Hail Storm·45 Nightmare·Paradise·Frozen threshold·Rara Avis·Nightshade
Sunrise·Wave of Spring·Snake in the Grass·First Flight·Asterisk·Burrs and the Bees·Egg Basket·Tire Swing·Early Frost·Beeline·Blossoms·Colorful Caterpillar·Seedlings·Rainbow·Max Fling·Avoid Tackiness·Egg Hunt·Woodpecker·Egg Drop·Heavy Rain·Easter Eggs·Daisy Cutters·Chipping In·Spring Freeze·Angry Monkeys·Upside Down Pilots·Below Ground·Drop Time·One of Each·Tulips·Broken Flower Pot·Bobbing Carrots·Breakthrough·Flower March·We Three Eggies·Sproing·Wallflowers·Bunch o Bees·Overdone·Eye of Spring·Sergeant Rabbit·Invasion·Spring TD·Prizes Inside·Get Those Flowers·Flower Buster·April Showers·Unwrap the Egg·Bloomin Boomin(secret level)·Beelay Race(secret level)
Frozen Core·Steamin Chowda·Spikes n Tacks·Bring Down the House·Ice Flake·Winter Journey·Return Flight·Tip of the Icebergs·Icy Peak·White Out·Bloom Box·Spike Run
Now You See 'Em·Less is More·Valuable Cargo·Overlap·Hidden Targets·Buds Bees Bombs·Reverse Gravity·Bloon Valley·Stealthy Fly By·Choices·Honey Pot·Gravity Wave
Dig That Plateau·Ups and Downs·Both Sides·Flowering·Two Targets·Simultaneous Combustion·Multi Bank·Moving Targets·Camo Tactic·Cracked Ceiling·In My Sights·Beaten Path
Snow Blockade·Rotations·Gopher Bloons·Bullseye·Bloons Super Monkey·Windows·Leaky Buckets·Ice and Fire·Openings·Ring 'Round the Rosie·Plunder Under·Cold Core