This one can be tricky, because your are changing the appearance of the substance. But here, you aren't changing its chemical form, so its a physical change. Even though you can't bring the pencil to its original beginning, its still a physical change.
Answer: Physical change.
<span>Let's look at all the statements:Which of the following statements is true?
Parts of an ecosystem only include biotic factors such as plants and animals. - this is not true, it also includes abiotic factors, such as stones
If a common plant in an ecosystem becomes diseased, the ecosystem may become unbalanced. - this is the true statement! it could be a source of food for other animals, and thus it could influence the population of other species
Abiotic factors include decomposers such as fungi and bacteria. - this is false, those are biotic factors.
Tundras have a high diversity of species. - this is not true - compared to the rain forest, for example, tundras are not very diverse</span>
I think that 3 is C and 2 is B
<span>When the surface layer was dug up, the permafrost was exposed. When the weather warmed, this exposed permafrost would have melted and become soggy, causing the ground underneath the tracks to shift.</span>
