A bacterium will make different proteins to metabolize the sugars lactose or glucose, depending on which of these it detects in the outside environment. What part of the bacterium allows it to recognize which substance is present in the outside environment? *

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers

d.embryo is the correct one