Rift valleys can form when fractures in Earth’s crust widen. The valley walls slowly move at a rate of only a few millimeters a year. Which of these best describes the type of tectonic activity that forms rift valleys?

Answer:

Iam not sure but I think it's position Y

The answer is Position X

Answer:

Our ancestors met astonishing challenges in their surroundings, and were susceptible to disease, injury, and predators. Environmental change – one of the ongoing challenges to survival – created both risks and opportunities in the lives of early humans.

Explanation:

environmental change. susceptible to disease, injury, and predators

Answer:

3) Chemical weathering changes the molecular structure of rocks and soil. For instance, carbon dioxide from the air or soil sometimes combines with water in a process called carbonation. This produces a weak acid, called carbonic acid, that can dissolve rock.

4) Soil erosion is a gradual process that occurs when the impact of water or wind detaches and removes soil particles, causing the soil to deteriorate. The impact of soil erosion on water quality becomes significant, particularly as soil surface runoff. Sediment production and soil erosion are closely related.

5) Natural soil erosion can play a beneficial role in the environment too. ... The erosion also helped cleanse the soil of any useless materials, such as rotting tree matter or nutrient-less dirt from the area. The replaced soil can often become nutrient-rich and help plant life thrive.

6) The effects of soil erosion go beyond the loss of fertile land. It has led to increased pollution and sedimentation in streams and rivers, clogging these waterways and causing declines in fish and other species. And degraded lands are also often less able to hold onto water, which can worsen flooding.

Explanation:

3) Chemical weathering changes the molecular
structure of rocks and soil. For instance,
carbon dioxide from the air or soil sometimes
combines with water in a process called
carbonation. This produces a weak acid, called
carbonic acid, that can dissolve rock.
4) Soil erosion is a gradual process that occurs
when the impact of water or wind detaches and
removes soil particles, causing the soil to
deteriorate. The impact of soil erosion on water
quality becomes significant, particularly as soil
surface runoff. Sediment production and soil
erosion are closely related.
5) Natural soil erosion can play a beneficial role
in the environment too. ... The erosion also
helped cleanse the soil of any useless
materials, such as rotting tree matter or
nutrient-less dirt from the area. The replaced
soil can often become nutrient-rich and help
plant life thrive.
6) The effects of soil erosion go beyond the loss of fertile land. It has led to increased pollution and sedimentation in streams and rivers, clogging these waterways and causing declines in fish and other species. And degraded lands are also often less able to hold onto water, which can worsen flooding..

Explanation:

Blood has various functions that are central to survival. They include:

supplying oxygen to cells and tissuesproviding essential nutrients to cells, such as amino acids, fatty acids, and glucoseremoving waste materials, such as carbon dioxide, urea, and lactic acidprotecting the body from diseases, infections, and foreign bodies through the action of white blood cellsregulating body temperature