The right answer is D) a structure made of two or more tissues functioning together for a common purpose.
An organ is a set of specific tissues capable of performing one or more specific functions. The human body has 78 organs and these organs can be grouped into systems (there are 11 of them) to perform more complex functions. For example, the bronchi and lungs are organs that belong to the respiratory system. Organs are necessary to live in good health and some organs are essential. These are the brain, heart, lungs, kidneys, liver and pancreas.
It is the Epithelium and blood-forming tissue. Endothelial cells are epithelial cells that shape a thin layer of straightforward squamous epithelium known as the endothelium. Vein endothelium is nonstop with the inward tissue coating of organs, for example, the mind, lungs, skin, and heart. Endothelial cells are gotten from endothelial undifferentiated organisms situated in bone marrow.
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>
Answer:
A vacuole is used for temporary storage of water, waste products, food, and cellular material. ... Vacuoles are larger in plant cells than animal cells to store the water and other materials needed by the cell.
