I would say B because c and d would decrease competition and a would do the same, or just kill the ecosystem.
Hope this helps and don't forget to hit that heart :)
Electrons are only
about 0.054% as massive as neutrons and protons are only 99.86% as massive as
the neutrons. The mass of the Proton is 1.67 x 10^-27 kg and the mass of the electron
is 9.11 x 10^-31 kg. The mass of the electron is so much lighter than the mass
of the proton.
The spaceship does not have any gravitational pull. A spaceship can not produce its own gravity like Earth does.
N = (PV)/RT
(T = 88.78 + 273 = 361.78K)
(R = 22.4/273 = 0.082)
= (5.49 x 22.03)/(0.082 x 361.78) = ?
Put it into the calculator. It's hard to do that on a mobile phone.