Why can only massive stars form black holes ? ( describe )

the natural consequence of the evolution of massive stars. Neutron stars have an upper mass limit of 2 to 3 solar masses. A collapsed object of greater mass will continue to collapse indefinitely, forming a black hole.

european union policies. the eu's long-term objective is to achieve levels of air quality that do not result in unacceptable impacts on, and risks to, human health and the environment. eu policies aim to reduce exposure to air pollution by reducing emissions and setting limits and target values for air quality.

the main environmental problems in western europe were: energy production/acid rain, nuclear power/waste, air pollution/climate, heavy metals, pesticides, water pollution, solid waste, and unforeseen accidents. many environmental problems are common to most european countries.

what school and grade?