Answer:
Smaller the size of the DNA fragment, farther it moves during electrophoresis. The sketch of the position of the fragments has been drawn in the figure below.
Explanation:
As we know DNA is a negatively charged molecule. So during electrophoresis the fragments move towards the positive electrode because opposite charges attract each other.
Different fragment move different distances according to their size during the electrophoresis. Smallest segment travels the largest distance in the gel medium while the largest one travels least distance.
In the question there are four DNA fragments with base pairs 4000, 2500, 2000 and 400 so the smallest segment with 400bp will be farthest from the starting point and the largest fragment with 4000bp will travel least distance in the gel medium. Their respective positions are shown in the figure below. The starting point is near the negative electrode.
The answer is B. Genetic drift greatly affects small populations, but large populations can recover.
By squeezing the food and pushing it towards the digestive juices in your stomach
Answer:
A scientific law is simply an observation of the phenomenon that the theory attempts to explain. For example, suppose that you were lying under an apple tree and observed an apple fall from a branch to the ground. The observation of this phenomena can be called the law of gravity.
Answer:
Explanation:
Food webs describe the relationships — links or connections — among species in an ecosystem, but the relationships vary in their importance to energy flow and dynamics of species populations. Some trophic relationships are more important than others in dictating how energy flows through ecosystems. Some connections are more influential on species population change. Based on different ways in which species influence one another, Robert Paine proposed three types of food webs based on the species of a rocky intertidal zone on the coast of Washington (Ricklefs 2008, Figure 2). Connectedness webs (or topological food webs) emphasize feeding relationships among species, portrayed as links in a food web (Paine 1980). Energy flow webs quantify energy flow from one species to another. Thickness of an arrow reflects the strength of the relationship. Functional webs (or interaction food webs) represent the importance of each species in maintaining the integrity of a community and reflect influence on the growth rate of other species' populations. As shown in Figure 2, limpets Acmaea pelta and A. mitra in the community consume considerable food energy (energy flow web), but removal of these consumers has no detectable influence on the abundance of their resources (functional web). The most effective control was exerted by sea urchin Stronglocentrotus and the chiton Katharina (Ricklefs 2008).
