The Professor gives examples of the effects of elephants on the African grasslands habitat. Using the examples from the talk, explain why elephants are considered a keystone species. v.1

We are living in the modern times of technology revolution, that is to say, travelling outer space no longer happens from science-fiction movies as nowadays people with the aid of modern high tech are feasible to explore to our universe. Nonetheless, this is not an affair which any country can do yet as it is reliant on many conditions, especially the financial one. Hence, basically I bet the government should be carefully concerned about investing resources to space exploration. It is understandable to say that space exploration is just for developed nations because in order to launch a manned spacecraft into the galaxy, they must have been well prepared for it, for example, the passengers need to qualify the simulator trainings in zero gravity conditions from the ground, or acclimatise to the distinct environment after landing on another planet. In fact, this contains risks which not every country can deal with. On the other hands, instead of investing a fortune in this kind of risky activity, mayors can better spend on solving problems existing on the Earth, for instance, the overpopulation, air pollution, polluted water and so forth. In term of preserving the terrestrial climate, although many activists campaign to protect our environment, the space industry seems to go in the opposite direction. To illustrate, after spending months abandoned and unused in the universe, the Skylab had inevitably crashed in an uninhabited area since 1979 while accidentally wasting junks into the atmosphere. To conclude, this depends on many requirements and also conceals risks which we have to work on it in advance. Hence, I think governments focus on tackling with existing issues on Earth rather than throw away money through this.