According to the universal law of gravitation
a. everything has a gravitation force because everything has mass.
b. not everything has a gravitational force because not everything existed when gravity first existed.
c. gravity is uniform across the universe.
d. gravity only depends upon the mass of an object.

the invasive species was introduced due to commercial purpouses, as there was a demand for fur clothes and hence, a business opportunity connected to this product. actually, it was when the nutrias scaped, causing harm to the us ecosystems when they acquired the status of invasive species. in this case they have caused an environmental problem, but it could have affected also economic interests or even human health.