Changing environments and ecosystems were driving the evolution of horses over the past 20 million years. ... "According to the classic view, horses would have evolved faster in when grasslands appeared, developing teeth that were more resistant to the stronger wear that comes with a grass-dominated diet
Answer:
If the petri plates are kept open for the longer duration of time then there are chances of cross contamination.
The contamination can be defined as growth of undesired microbes in the petri dishes or tubes which is no longer useful for the experiment.
The tube if kept open will develop the growth of contaminants in it. It can be cross contamination as well.
To avoid contamination the tubes and dishes should not be kept open for a longer duration of time.
I disagree it should be A
No. Biotechnology is a refinement of breeding techniques that have been used to improve plants for thousands of years. The 20th century, in particular, saw the development and application of many new techniques to transfer genes between related and even unrelated species for crop improvement. Biotechnology is the latest in a long line of increasingly powerful tools for enhancing crops.
The smallest group in the Linnaeu's system of classification is Morphology.