<span>The muscles that can flex, extend and abduct the arm, are the voluntary muscles, such as the biceps, triceps, and delts. These muscle play a crucial role in mobility of the arm.</span>
<span>
Answer: 5% to 20% </span>
Energy flow can be defined
as the amount of energy that moves through a food chain and it flows through
ecosystem in one direction. Thus, the largest source of energy for an ecosystem
is the sun and the energy that enters the ecosystem is usually measured in
calories or joules.
Answer:
B) There is an increase in the number of giraffes with long necks in areas of Africa where low-growing trees have died
Explanation:
The directional selection is one of the ways of the natural selection in which the natural selection selects or favours the most extreme trait of the species and the extreme trait show higher fitness than the normal or average trait.
In the given question, the case of Giraffe necks shows directional selection as the normal length of the neck is not favoured by the environment but the extreme trait that is long neck is favoured by the environment and the selection shifted to that level.
Thus, Option-B is the correct answer.
