Why are there hundreds of different protein channels

Look at the picture below . what does this picture represent ?

The terrestrial planets are characterized by having a a.) silicate core b.) iron-rich silicate core c.) iron-rich metallic core d.) none of these

Plz fast biotechnology is a growing field of applied biology. many crops such as corn have been engineered to be resistant to herbicides. therefore farmers can spray these chemicals to kill weeds growing near the crop without worries of killing the crop itself how does this type of biotechnology work? a. by changing the genetic make up of the crops. b. by causing the crops to kill the weeds. c. by changing the type of crops used. d. by changing the location of the crops.