15
Each one of those letters represents a nucleotide. So to find out how many nucleotides are in the gene, just count them
However, keep in mind that this only represents 1/2 strands that make up DNA. If you are supposed to include the other strand, simply double 15, and there would be 30 nucleotides total. However, only 1 strand is actually required in order for protein synthesis to work, so I think it's just 15.
Answer: b - Chondroblasts within the cartilage divide and secrete new matrix
Explanation: Chondroblasts are derived from two sources; mesenchymal cells within the center of chondrification and chondrogenic cells of the inner cellular layer of the perichondrium (coverings that lie over most cartilage).
At the chondrification centers, the cartilage forming cells (Chondroblasts) begin to secrete the components of extracellular matrix of cartilage. As the amount of matrix increases, the Chondroblasts become separated from each other and they are located in small cavity within the matrix called lacunae.
Concurrently, the cells differentiate into matured cartilage cells called chondrocytes.
Rocks are abiotic
(Soil?) is made of both abiotic and biotic materials
Sea shells are biotic
The answer is B. The cardiac, respiratory, and vasomotor
control centers are in the medulla. This means that the medulla controls heart
rate, blood pressure, breathing, and the size of the body's blood vessels. They
have chemoreceptors, pH sensing structures that detect levels of carbon dioxide in the blood and adjust the breathing rate accordingly.