Which statements are examples of observations a scientist would make to classify a rock? check all that apply. a rock is larger than other rocks. a rock feels smooth to the touch. a rock is formed from molten lava. a rock is made of different minerals. a rock cracks in half after a rainstorm.

A rock feels smooth to the touch.

A rock is formed from molten lava.

A rock is made of different minerals.

A rock feels smooth to touch

A rock is made from different minerals

A rock cracks in half after a rainstorm

Explanation: A rock is a substance that is an aggregate of one or more minerals. The rocks are formed by the natural processes like volcanic eruption, weathering and erosion. These rocks can be distinguished on the basis of their physical and chemical properties. Like color, texture, mineral and chemical content, solubility in a solvent.

On the basis of the above information a rock can be classified on the basis of A rock feels smooth to touch, A rock is made from different minerals, A rock cracks after a rainstorm are correct options.

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.