This is because butterfly caterpillars are host specific. Plant-wise, the caterpillars of some butterfly species like asters, black-eyed Susan, clover, lupines, milkweed, sedum or violets. Aspen, birch, cherry, hackberry, oak or willow trees make caterpillars of other butterfly species equally happy.
each Br-F bond would be polar or BF4-, there is an extra electron making this a polar molecule. PCl5 has the Cl atoms that must be as far apart from each other as possible and therefore would create equal but opposite pulls.ach Br-F bond would be polar or BF4-, there is an extra electron making this a polar molecule. PCl5 has the Cl atoms that must be as far apart from each other as possible and therefore would create equal but opposite pulls.
This is the role of plasticisers and such process is technically called plasticising. PVC polymer molecules have positive and negative polarities inside, while plasticiser molecules also have such polar and non-polar parts.he PVC polymer molecules and the plasticizer molecules are electrically attracted to each other, and the non-polar parts widen the distance among the polymer molecules to keep softness. PVC products which are softened by plasticisers are called soft (flexible) PVC products.