Answer:
Scientists usually use the potassium-argon method to date rocks that are older than about 1 million years. Uranium-238 is also used for radiometric dating. It has a half-life of 4.5 billion years. It decays to produce lead-206.
Answer:
DNA vaccines consist of DNA vectors or plasmids (small double-stranded DNA rings originally derived from bacteria, but unable to cause infection) into which the genes encoding one or more immunizing proteins of the infectious agent have been inserted causing the disease to be prevented.
Explanation:
Vectors are the functional unit of naked DNA vaccines. Genes that encode the proteins of interest and are of bacterial origin are inserted into these vectors. Bacterial plasmids are circular DNA molecules that self-replicate extrachromosomally in bacteria. The genes encoded in these plasmids are under the control of promoters, almost always of viral origin. When a plasmid is introduced into the cell it translocates to the nucleus, where transcription of the transgene begins; the transcripts are then taken to the cytoplasm and translated there. The newly synthesized proteins are degraded in the proteasome to 8-10 amino acid peptides, which are transported to the endoplasmic reticulum. Peptides of high affinity with their respective MHC I molecule stabilize and enter the secretory pathway, thus reaching the cell surface, where they are coupled with the T-lymphocyte receptor (TcR) present on the surface of T lymphocytes cytotoxic drugs (CD8 +) to induce their activation.
The Fossil Record. Fossils provide evidence that organisms from the past are not the same as those found today, and demonstrate a progression of evolution. Scientists date and categorize fossils to determine when the organisms lived relative to each other.
Brainliest please
Methane is the gas that is strongly correlated with Earth's heating and cooling patterns. Did you know that cow's flatulence is methane gas?! Interesting fact!
