Answer:
a
Explanation:
inside a volcano is chloroplast the lava
A plant cell contains a large, singular vacuole that is used for storage and maintaining the shape of the cell. In contrast, animal cells have many, smaller vacuoles. Plant cells have a cell wall, as well as a cell membrane. Animal cells simply have a cell membrane, but no cell wall.
Liquid and gas takes the shape of their container.
Answer: Vasodilation of the arteries lowers blood pressure and decreases the force that the heart muscle needs to exert to pump blood., the cell signaling mechanism begins when $NO$ diffuses into the smooth muscle cells of the blood vessel and activates guanylyl cyclase.
Explanation:
Answer:
2.7 billion
Explanation:
This period is referred to as the Great Oxygenation Event. This period saw the evolution of photosynthetic organisms (cyanobacteria) that utilized carbon dioxide (that dominated the atmosphere then) and sunlight to manufacture their energy molecules-glucose. Photosynthesis produces oxygen as a byproduct that is evolved into the atmosphere. As these photosynthetic organisms proliferated on earth, the atmosphere composition changed to become partly dominated by oxygen (which is an oxidaton agent) with less and less carbon dioxide.
