The correct answer is the organ.
The multicellular species are formed of various parts, which are required for survival. These parts are differentiated into the levels of the organization. There are five different levels, which are named as cells, tissue, organs, organ systems, and organisms.
When two or more layers of tissue function together, they produce an organ. All the animals comprise vital organs, without which they cannot survive. These include the kidneys, liver, lungs, brain, and heart.
President Lincoln said the "insurgents" wanted to fight because they wanted to extend and perpetuate slavery. At the end of the Civil War, the "insurgents" did not get their wish. The correct answer is B.
D. Number of protons in an atom's nucleus
Embryophyta is a clade within the Phragmoplastophyta, a larger clade that also includes several green algae groups. Embryophytes are the plants growing on land which include hornworts, liverworts, gymnosperms, flowering plants etc while green algae mostly thrive in aquatic environment.
The conduction of water requires vascular tissue called xylem. In green algae, it is not necessary to have water conducting tissue as the entire body is in contact with water. However in embryophytes, having a vascular tissue is an adaptation that ensures to provide water to the higher parts of the plant which is not directly in contact with the soil.
