Why do scientists track virus mutations and how might tracking these variants be helpful in preventing and treating the virus?

Which is the completely factored from of xy^3-x^3y

Let hh represent the number of hummingbirds and ss represent the number of sunbirds that must pollinate the colony so it can survive until next year. 6h+4s > 746h+4s> 74 this year, 88 hummingbirds pollinated the colony. what is the least number of sunbirds that must pollinate the colony to ensure that it will survive until next year?

Triangle dog was rotated to create triangle d'o'g'. describe the transformation using details and degrees.