Answer:
If an individual Drosophila has two or more populations of cells comprising different genotypes from one single egg then it is termed as twin spots or mosaic.
Explanation:
There might be different reasons for mosaic to occur like
Nondisjunctioning of the chromosomes
Lag in anaphase
Endoreplication
Mutations in a single cell
Mitotic recombination:
One of the major ways through which mosaic or twin spots arise is the mitotic recombination. It is also termed as somatic cross over. Twin spot or mosaic generally occurs if there is linking of heterozygous genes in repulsion. The recombination generally happens among the centromeres from the adjacent genes.
A common example of the mitotic recombination is the Bloom's syndrome. Bloom's syndrome is caused due to the mutation that occurs in the <em>blm</em> gene. As a result, there are defects in the BLM protein produced.
Answer:
Option D, a test for the presence of cells that contain DNA
Explanation:
As we know all living organisms are made up of cells and DNA is the basic genetic material that codes for protein and traits with an organism. If even a single cell with DNA is detected on the extraterrestrial planet then it will be clear that it has life on it or the environmental conditions are favorable to support life. Cells are microscopic and hence can be seen through microscope which can be installed easily on a probe.
Hence, option D is correct
Answer:
When sulfurous, sulfuric, and nitric acids in polluted air and rain react with the calcite in marble and limestone, the calcite dissolves. In exposed areas of buildings and statues, we see roughened surfaces, removal of material, and loss of carved details. Stone surface material may be lost all over or only in spots that are more reactive.
Explanation:
You might expect that sheltered areas of stone buildings and monuments would not be affected by acid precipitation. However, sheltered areas on limestone and marble buildings and monuments show blackened crusts that have peeled off in some places, revealing crumbling stone beneath. This black crust is primarily composed of gypsum, a mineral that forms from the reaction between calcite, water, and sulfuric acid. Gypsum is soluble in water; although it can form anywhere on carbonate stone surfaces that are exposed to sulfur dioxide gas (SO2), it is usually washed away. It remains only on protected surfaces that are not directly washed by the rain.
The correct answer is D) The fossil record reveals intermediates that link different species. Hope this helps.
