Answer:
When sand is already present in a valley and more sand is deposited on top, it becomes a sand dune. As more sand is deposited, the dune gets bigger. Slowly but surely, the sand fills up the valley, until the valley is non-existent, but level to the ground.
Answer:
Models help us to get a better understanding of structures and processes which otherwise would have been difficult to understand. Models illustrate structures ans processes in the form of chemical equation, mathematical equations, computer simulations, drawings etc.
The building of a carbon molecule will help us understand the structure of a carbon atom and the various bonds that it can form, The model will be able to depict the various ways in which the electronic configuration of the carbon atom can change to form different compounds.
Answer:
97% of american farms are family opertaed.
Explanation:
<span>A)ecosystem - this is true! an ecosystem includes both living and non-living objects in a system!
b. population - this is only biotic: a population is a group of organisms, and organisms are biotic
c. biome - this is also only biotic: it's a large community of plants and animals over a large area
d. organ
- this would be only biotic (parts of living organism)</span>