Which statements are correct about a group? the elements in each group have similar chemical properties. the elements in each group have identical physical properties. the atomic number of each element increase by 7 down through the group. each member of the group has the same number of electrons in the outer shell.

why is arctic sea ice important? arctic sea ice keeps the polar regions cool and moderate global climate. sea ice has a bright surface; 80 percent of the sunlight that strikes it is reflected back into space. as sea ice melts in the summer, it exposes the dark ocean surface.

one negative thing it that it can kill water animals. another negative thing is it can cause the destruction of ecosystem. one way water pollution can be reduced is to conserve energy.