There is a community of organisms but no no living components
There are all sorts of ways to reconstruct the history of life on Earth. Pinning down when specific events occurred is often tricky, though. For this, biologists depend mainly on dating the rocks in which fossils are found, and by looking at the “molecular clocks” in the DNA of living organisms.
There are problems with each of these methods. The fossil record is like a movie with most of the frames cut out. Because it is so incomplete, it can be difficult to establish exactly when particular evolutionary changes happened.
Modern genetics allows scientists to measure how different species are from each other at a molecular level, and thus to estimate how much time has passed since a single lineage split into different species. Confounding factors rack up for species that are very distantly related, making the earlier dates more uncertain.
These difficulties mean that the dates in the timeline should be taken as approximate. As a general rule, they become more uncertain the further back along the geological timescale we look. Dates that are very uncertain are marked with a question mark.
Answer:
The correct answer is- B) Cell walls are made primarily of peptidoglycan
Explanation:
There is a difference between the cell wall of bacteria, archaea, and eukarya. The cell wall of bacteria is primarily made up of peptidoglycan which contains two sugar N-acetylglucosamine and N-acetylmuramic acid while archaea contain two N-acetyltalosaminuronic acid (NAT) in place of N-acetylmuramic acid which is called pseudo-peptidoglycan.
Eukaryotic cell wall is also different from archaeal and bacterial cell wall and animals in eukaryotes do not have a cell wall. Therefore cell wall made up primarily of peptidoglycan will allow you to classify the organism as belonging to Bacteria but not Archaea or Eukarya.
Answer:
Ocean currents are the continuous, predictable, directional movement of seawater driven by gravity, wind (Coriolis Effect), and water density. Ocean water moves in two directions: horizontally and vertically. Horizontal movements are referred to as currents, while vertical changes are called upwellings or downwellings.They carry cold water from the poles to the equator and cool air over land. They move warm water from the equator to the poles and heat air over land.
Explanation:
They carry cold water from the poles to the equator and cool air over land. They move warm water from the equator to the poles and heat air over land.
