The vertebral column, when seen from the side, has 4 curves: 2 convex curves (cervical and lumbar curves) and 2 concave (thoracic and sacral curves). This curves are the feature of the skeleton that allow a child to maintain balance in the upright position eventually.
When we are born we have a single concave curve throughout the whole vertebral column but, as we grow, still in the early months as we try to hold our head, the cervical curve starts to develop, and later, as we try to sit up, stand up, and walk, the lumbar curve aslo starts to develop. In few years we have all curves fully developed.
Correct answer - Replace Thymine (T) with uracil (U) in the DNA molecule.
Why? - As the RNA polymerase continues down the strand of DNA, more nucleotides are added to the mRNA, thereby forming a progressively longer chain of nucleotides. This process is called elongation. DNA (top) includes thymine (red); in RNA (bottom), thymine is replaced with uracil (yellow).
The three most common elements are oxygen, carbon, and hydrogen
Pretty sure its a.) the umbilical cord carries the metabolic waste from the fetus to the placenta where it diffuses into the maternal blood.
Bc metabolic waste just goes from the umbilical cord to the mothers blood
