Species change over time. -The mechanism that produces the change is natural selection: the differential survival and reproduction of individuals based on variation in their traits. Natural selection acts on individuals but individuals do not evolve; their descendants do.
Answer:
Trapezius.
Explanation:
Sternocleidomastoid muscles may be defined as one of the largest superficial cervical muscle. The main function of this muscle is the neck flexion and the head rotation.
Trapezius muscle is the large muscle that extend from the occipital bone. The main function of the trapezius muscle is the scapula movement and support of the arm. Trapezium muscle resist the neck flexion and works as the antagonist to the trapezius muscle.
Thus, the answer is trapezius.
it is not because trees do not grow fast enough
Answer:
They have helical thickening of lignin in their walls to prevent collapse
Explanation:
the primary function of Xylem and its conducting vessels tracheids is to provide support and tranport water and minerals in plants.
Xylem vessels have layers of dead materials in the walls called LIGNIN. Lignin is a polymer; a very strong, hard materials that stop water passage through it,because it contains dead cells,
Therefore the presence of deposit of these strong impermeable, ligified walls in its walls prevent its collapse during mass flow of water of transpiration pull.
Although amino acids may have other formulas, those in protein invariably have the general formula RCH(NH2)COOH, where C is carbon, H is hydrogen, N is nitrogen, O is oxygen, and R is a group, varying in composition and structure, called a side chain.
