Answer: i think its protons and electrons but it also might just be atoms because protons and electrons make atoms when there are also neutrons
Explanation:
7.30 x 10^-7 km. the others have 4 significant figures.
K + I - > KI
Potassium (needs to lose 1 electron) responds with Iodine (needs to pick up 1 electron) to fulfill both component's octet, shaping a salt, potassium iodide
This is a similar case for NaCl, simply unique components. Trust this made a difference.
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 :)
