A random person put the answer for you
I would say the first three. But I'm not 100% sure. I'm truly sorry if it's wrong
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 :)
Water deposits soil ,sediments ,and rock by moving them to a different place .Say like a beach .The ocean is currently moving the bits of sand and (glass:sand)rock pieces and always ending up in new places.Same as a river.!!!!
I suck at chemistry but i have a friend that can help