Answer:
D, think of chemical changes. When iron rusts it is chemically changed. The other answers are a change in form or a property of iron.
The answer to your question is B.
Answer:
Primary succession is one type of the ecological succession which takes place on the land devoid of vegetation or barren land.
The species which first flourishes on this barren land are known as pioneer species which includes the species of bryophytes and pteridophytes like lichens and mosses.
These lichens and mosses help breakdown the barren rocks through chemical leaching and help increase the nutrient content. This allows the ferns and small pteridophytes to grow.
Then the area is colonized by the intermediate species which includes herbs, shrubs later trees. These intermediate species help attract the animals and thus help establish the biological community.
Thus, Lichens mosses → herbs→ shrubs →trees.
"Gravitational attraction" is initially responsible for the formation of the clumps of matter within this interstellar cloud.
<u>Answer:</u> Option C
<u>Explanation:</u>
About 4.6 billion years ago, the solar systems were a bunch of gases and dusts, referred to solar nebula. Gravity squeezed the material as it started to rotate, creating the sun at the middle of the fog.
The rest of the material began to accumulate with the sunrise. The smaller particles moved together to form larger particles that were connected by gravity. As lumps develop, gravity increases and turns into kinetic energy of moving particles that collide and produce heat.
