Question

Choose . the workers were throwing toxic waste _____ the river
by
for
into
up ​

Answer 1

it can be either my bad for the unclear answer

Answer 2

Into

Step-by-step explanation:

Say each choice and see if each one makes sense.

The workers were throwing toxic waste by the river? No.

The workers were throwing toxic waste for the river? No.

The workers were throwing toxic waste into the river? Yes.

The workers were throwing toxic waste up the river? No.