The two correct responses are:
- They are explosive events that can affect Earth.
- They appear as dark spots on the sun's surface. (This is not correct; dark spots refer to sunspots, not flares or CMEs.)
Given the options, the only correct response related to solar flares and coronal mass ejections (CMEs) is that they are explosive events that can affect Earth. The statement about appearing as dark spots is not accurate for flares and CMEs. Therefore, if you need only one correct response focused on an actual commonality, it is the one about explosive events affecting Earth.