Answer:
1.
Explanation:
Xylem cell is a plant vascular tissue that conveys water and dissolved minerals from the roots to the rest of the plant and also provides physical support. Xylem tissue consists of a variety of specialized, water-conducting cells known as tracheary elements.
2. Phloem is the vascular tissue in charge of the transport and distribution of organic nutrients. The phloem is also a pathway to signaling molecules and has a structural function in the plant body.
3. Stomata are composed of a pair of specialized epidermal cells referred to as guard cells. Stomata regulate gas exchange between the plant and environment and control water loss by changing the size of the stomatal pore.
4. Guard cells optimize leaf gas exchange in response to changing environmental conditions and their turgor is controlled by alterations in atmospheric CO2 concentration, light intensity, humidity, and the drought hormone abscisic acid.
The effect that malnutrition have on the fetus during critical development in pregnancy is that the impairment of the development of an organ is irreversible. Maternal malnutrition can adversely affect the division and replication of cells in the embryo at this stage, impairing its development. The effects of malnutrition during critical periods of pregnancy are seen in defects of the nervous system of the embryo, poor dental health among other effects.
Mitosis is used to produce daughter cells that’s genetically identical to parent cells. And Mitosis affects change by the cell copying or “replicating” its chromosomes, and then splitting the copied chromosomes equally to make sure that each daughter cell has a full set.
(Rice) is a Complex carbohydrate because they are made of sugar molecules strung together in complex strands.
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>
