The Twenty-Nine Palms Marine Base in the Mojave desert is a habitat for both desert tortoises and ravens. The ravens (R), prey on the baby tortoises (T). Based on the following assumptions, write a differential equation model for these populations. . Since it takes tortoises about 20 years to reach sexual maturity and they can live up to 80 years, the baby tortoise birth rate is proportional to the baby tortoise population 30 years earlier, with a proportionality constant of 1.8. . The rate at which an individual raven preys on tortoises is a saturating function of the baby tortoise population, with a maximum of 0.5. . Baby tortoises die from causes unrelated to raven predation at a constant per-capita rate of 0.02 and mature into adults at a per-capita rate of 0.06. . Since ravens have other food sources, their per-capita birth rate is a constant, 5. . The per-capita death rate of ravens is proportional to the raven population with a proportionality constant of 0.02. . The Marines are using lasers to drive ravens off the base. The rate at which they do so is a sigmoid function of raven abundance that increases up to 0.8 when the raven population is high