I've actually learned something similar recently so your best bet is to go with B.
Answer:
, tree rings usually grow wider in warm, wet years and they are thinner in years when it is cold and dry.
Explanation:
Answer;
-Mitochondria
Explanation;
-Mitochondria is a cell organelle where ATP is generated, it act as a powerhouse of the cell. ATP is generated through the process of cellular respiration.
-Cellular respiration is the process by which cells break down nutrients such as glucose to release energy in form of ATP, which is used by the cells to drive cellular processes such as growth and transport. The process involves three stages ; namely, glycolysis, citric acid cycle and electron transport chain, when oxygen is present.
One activity would be logging of trees, which could be selective or clear cut. It is done to provide wood for building houses and for pulp for paper primarily. A short term effect would be loss of habitat for forest wildlife and removal of vegetation and it could result in increased erosion if in a mountainous area. Loss of old growth forest possible too. Long term effect if re-forested could be partial restoration of habitat. Another activity is open pit mining whereby the land where the orebody is is cleared and mining creates sometimes large holes in the ground and removes old lake habitats for migratory birds and fish in the short term.The purpose of the mining is partly to provide metals to society. The long term, if adequate reclamation of waste dumps is undertaken, can lead to extensive new grasslands on the dumps and forage for deer and moose and sometimes cattle. Oil production and transport on oceans can lead to oil spills such as occurred off Valdez in the 1980's or in the Gulf of Mexico recently and the short term is soaking marine animals with oil and killing many of them and contaminating beaches and shorelines. Some clean-up can be done but the long term effects of this activity may still be unknown. The oil is for fossil fuel for internal combustion engines but it will need to be replaced by say, electric cars for the future ie to clean energy. Another general effect of this time, the use of fossil fuels is from global warming is creating more and more intense hurricanes such as occurred in the Caribbean this fall in Cuba, Florida, Dominca and Puerto Rico in particular with the result of widespread damage or destruction of people's houses, flooding, loss of power and costly repairs and loss of life. Only by limiting the production of greehouse gases by mankind will there be a chance to reduce the incidence and intensity of such events.
Answer;
-Phospholipids and protein
Explanation;
-The plasma membrane is composed of a phospholipid bilayer arranged back-to-back. It is also covered in places with cholesterol molecules and proteins. The plasma membrane is selectively permeable and regulates which molecules are allowed to enter and exit the cell.
- The membrane is an extremely thin layer of lipids and protein that forms outer boundary of every cell, It controls movement of molecules between the cell and its environment, Participates in joining cells to form tissues and organs and also plays important role in the ability of a cell to respond to changes in the cell's environment.