There are two pairs of competing species of ferns. species a and species b have carrying capacities of 10,000 and 6,000, respectively. the competition coefficient of species a on species b is 0.25 and the competition coefficient of species b on species a is 2.5. species c and species d have carrying capacities of 8,000 and 14,000, respectively. the competition coefficient of species c on species d is 0.1 and the competition coefficient of species d on species c is 0.2. based on the lotka-volterra equation, which of these pairs of species can coexist?