Which of the following statements about the interaction of earth’s systems is true?
a.
the interaction between earth’s systems is limited to a response to human activity.
b.
the earth’s system interact using positive feedback only.
c.
the earth’s systems interact using negative feedback only.
d.
all of the earth’s systems interact with each other.

The correct answer is option d. "All of the Earth’s systems interact with each other".

Explanation:

Earth’s systems are interconnected parts that by functioning in harmony allow that the planet maintain a relative equilibrium. The five major systems of the Earth are Geosphere, Biosphere, Cryosphere, Hydrosphere and Atmosphere. All of the Earth’s systems interact with each other and anything that would affect any of the systems, affects all of them.

advantage of using stem cells in medical research:

1.       it provides medical benefits in the fields of therapeutic cloning and regenerative medicine.

2. it provides great potential for discovering treatments and cures to a variety of diseases including parkinson disease, spinal cord injuries, diabetes, alzheimer’s disease and many more.

3. limbs and organ could be grown in lab from stem cells and then used in transplant or treat illness.

americans began to notice growing differences between the northern and southern sections of the country. there were more people living in cities in the north, which made it more urban. more people lived on farms in the south, which made it more rural. while many people were farmers in the northern states, there were now other ways to make a living, such as working in mechanical cotton gins factories manufacturing cloth, tools and other goods. people in the north supported high tariffs on goods imported from europe because the extra cost encouraged people to “buy american” instead. in the southern states, planters did not like tariffs because they sold most of their production to europe and bought their tools from there as well. southerners believed the protective tariff was something that only northern factory owners keep their profits high. so the southern politicians came up with an idea. they would opt out. they would simply ignore the protective tariff. it was ‘null and void’ in south carolina. the state would not collect the taxes on goods imported into south carolina, no matter what the president said they had to do. this decision led to the nullification crisis.