I think the correct answer from the choices listed above is option A. It is the alveoli that is composed of single layer <span>surrounded by a network of capillaries. These are used to allow oxygen and carbon dioxide to move from the lungs to the bloodstream.</span>
Answer:
Nucleus
Explanation:
Expressing a gene basically means manufacturing its corresponding protein. This process has two major steps:
- In the transcription process, the information in DNA is transferred to a messenger RNA (mRNA) molecule. This first major step of gene expression and genetic splicing of exons occurs in nucleus environment of the cell.
- During translation, which is the second major step, the mRNA is "read" according to the genetic code, which relates the DNA sequence to the amino acid sequence in proteins. Within all cells, the translation occurs within a specialized compartment called the ribosome.
Metaphase. During metaphase, spindle fibers attach to the centromere of each pair of sister chromatids The sister chromatids line up at the equator, or center, of the cell. The spindle fibers ensure that sister chromatids will separate and go to different daughter cells when the cell divides
<span> RNA was thought of as little more than a messenger between DNA and proteins, carrying instructions as messenger RNA (mRNA) to build proteins. However, RNA can do far more. It can drive chemical reactions, like proteins, and carries genetic information, like DNA. And because RNA can do both these jobs, most scientists think life as we know it began in an RNA world, without DNA and proteins.</span>
