Answer:
There are two types of ecological succession:
Primary succession:
Primary succession occurs in areas which were previously devoid of life. There were no organisms living in this area before. For example, lands after new glaciers or volcano eruptions. Firstly, microorganisms begin to habitat this land, followed by plants like lichens, shrubs etc. Finally, complex life evolved from these.
Secondary succession:
Secondary succession arises in areas where life existed before but was destroyed due to natural circumstances like flood, fire etc. Small grasses inhabit this land first which are taken over by trees over period of time.
<span>This is true. Surveillance can be performed efficiently through both stationary and mobile means. As far as human surveillance goes, people can track other people by tailing them or by using a stationary means such as a stake out. As far as technology goes, there are plenty of mobile devices that can be used for surveillance such as tracking devices. Security cameras can be used for stationary purposes.</span>
Answer: Stem cell research has the potential to treat diseases that are currently burdened with high health care costs—especially chronic conditions such as heart disease, Alzheimer's disease or diabetes, the costs of which threaten to cripple the healthcare system.
