A first-hand source such as an experiment is called a primary source.
A primary source is where you can share new information or report on what you have discovered. Some primary sources are research data, interviews, audio recordings, and autobiographies.
A secondary source is where you describe and discuss about the primary sources. They are used to collect and gather primary source information. Some secondary sources are textbooks, review articles, and scholarly books.
A tertiary source is a source about summaries. A tertiary source can be used to look up information or get an overview about what it is you are wanting to know. Some tertiary sources are dictionaries, handbooks, encyclopedias, Wikipedia, and guidebooks.
Answer:
cells
Explanation:
cells are responsible for the structures and functions
Answer:
The weight of an object at the surface of a planet is proportional to the planet's mass and inversely proportional to the square of the radius of the planet.
A) DNA fulfils all three conditions:
<span>(1) copy itself precisely - in the process of replication, DNA copies itself and two molecules of DNA are formed. This process is very precise thanks to the great number of proteins involved in these process that prevents error occurring and proteins that can fix the error if it occurs.
(2) be stable but able to be changed - DNA is very stable molecule otherwise, it cannot be a genetic material. However, its chains can separate in a short length so the translational machinery can attach to it and the process of transcription can occur. Also, in crossing over, during meiosis, </span>the exchange of genetic material occurs and chromosomes change a bit.<span>
(3) be complex enough to determine the organism’s phenotype - it contains a number of genes responsible for different traits. All of this results in the </span>organism’s phenotype.
B) DNA copies itself. <span>Meselson and Stahl conducted the experiments on DNA replication in which they used </span>E. coli<span> bacteria as a model system. After they labelled all bacteria's DNA with heavy 15N by using medium with heavy 15N, they switched bacteria to medium with light 14N. After several generations, all bacteria's DNA was labelled with light 14N. This experiment evidenced that the self-replication of DNA is semi-conservative process.</span>
Cells in the pancreas release insulin into the blood
