What causes the pressure that allows diamonds to form in the mantle? A. The sun's gravity acting on Earth B. The weight of the rocks in the outer core O C. The weight of the rocks in the crust and core D. The weight of the rocks in the crust and upper mantle

The us and canadian governments are doing all of the following to combat environmental problems except a. encouraging the use of public transportation b. enacting clean water policies c. requiring emissions testing d. limiting animal populations in some regions