How do scientists know that dark matter exists? A) It’s heat raises the temperature of space.

B) Its gravity affects objects around it.

C) It gives off electromagnetic waves.

D) All of these.

Ahis which describe the horizons in a soil profile? check all that apply. horizon a is mineral deficient. bedrock lies below the soil layers. te horizon o forms from organic material, horizon b undergoes the least amount of change. horizon c is least affected by the soil formation process.

Which of the following best describes the circumstance under which countries block the importation of certain products into their country? a. importation blockade b.trade barrier c.trade inhibitor d. domestic protection act

In a class of 20 students, what democratic form of governance makes the most sense