Explanation:
Karyotyping is <u>a test to examine chromosomes in a sample of cells</u>. This test can help identify genetic problems as the cause of a disorder or disease.

<span>The stage at which all the cells show crossover chromosomes is meiotic prophase I. The crossover is the exchange of genetic material between homologous chromosomes. Homologous chromosomes are present in the meiosis I. Regarding the phase of meiosis I, it is expected that the crossover takes place in meiotic prophase I since homologous chromosomes pair up in the prophase.</span>
Answer:
Stomata are the organs present on the stem and leaves of the plant and help in the gaseous exchange and evaporating water present in the aerial parts of the plant. Mainly leaves stomata plays role in gaseous exchange and transpiration which is the evaporation of the aerial water of plants by opening and closing the stomata. Stomata are small pores mostly and normally present under the leaves and regulated by the guard cells, dum bell shaped cells to close or close it.
Other than closing and opening the stomata, stomata density also can affect the rate of gas exchange as well as transpiration. Stomata density is the presence of the numbers of the stomata per unit area. In heat or sunny area the stomata density is higher than the shady or dark area to increase the transpiration in order to cool down the leaves of the plant which prevent the chloroplast proteins to denature.