Answer:
four
Explanation:
Carbon atoms have four electrons in their outer shell. So, it exhibits tetravalency & thus, a single carbon atom can form a maximum of four (4) bonds with other atoms
Answer:
B. Plants can make their own good
Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs.

Two identical copies formed by the replication of a single chromosomes