Answer: Humans first evolved in Africa, and much of human evolution occurred on that continent. The fossils of early humans who lived between 6 and 2 million years ago come entirely from Africa. Most scientists currently recognize some 15 to 20 different species of early humans.
Explanation:
Answer:
1. Based on their physical features and conduction properties
2. 80m/s to 120m/s
3. Has both sensory fibers and motor fibers
4. Group B conduct at 3m/s to 15m/s
5. Group C conduct at 0.5m/s to 15m/s
6. They generally have low conduction velocity and are polymodal
Explanation:
Axons were know to have different thickness and this differences were thought to relate to the speed at which the action potential could travel. This hypothesis was proved by Erlanger and Gasser.
Answer;
-Communities that experience moderate disturbances often exhibit greater species diversity than other communities,
-Moderate disturbances create openings/opportunities for colonizing species
Explanation;
-Ecological disturbances may be generated by abiotic, or nonliving, forces such as weather and wildfires, or they may occur as a result of biotic, or living, forces such as disease and invasions of exotic species.
-Disturbance can result from natural causes or from the activities of humans.
Disturbance can be caused by physical stressors such as volcanic eruptions, hurricanes, tornadoes, earthquakes, and over geological time, glacial advance, and retreat.
-Humans can also cause physical disturbances, for example, through construction activities. Wildfire is a type of chemical disturbance caused by the rapid combustion of much of the biomass of an ecosystem and often causing mortality of the dominant species of the community such as trees in the case of a forest fire.
Answer:
The answer is A. Nerve signals from the brain are controlling the arm.
Explanation:
Movement: the brain sends messages that control how your body moves.
Lemme know if this was right.
The student is actually doing replication
Answer: Option B
<u>Explanation:</u>
A student reads about a particular experiment, gets inquisitive to learn more and hence tries to copy that particular experiment. This is called as replication as the student tries the same methodology and process adapted to perform the experiment. He tries to obtain the same result.
This result fascinates him giving assurance of the experiment. It also helps motivate trying different experiments. It also inspires him to make further researches.