There are numerous things. They can give tax cuts to farmers and those who work in the agriculture sector. They can give subsidies to those people too. Both of these things motivate people to work in that field.
Would it be predators? Because predators can catch weaker older deer easier than younger healthier ones.
The rules of base pairing explain the phenomenon that whatever the amount of adenine (A) in the DNA of an organism, the amount of thymine (T) is the same (Chargaff's rule). Similarly, whatever the amount of guanine (G), the amount of cytosine (C) is the same.