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.
when cells spilt into 2 or more new cells
Answer:
Energy pyramids is representation of food chain where producers lie at the base of pyramid followed by primary, secondary and tertiary consumer. A tertiary consumer lies at the top of the energy pyramid .
Explanation:
An ecological pyramid is a chronological arrangement of organism in which the organism producing the food lies at the base of pyramid and remaining all organism lie above it.
Each level of an ecological pyramid is called a trophic level and an organism lying at any trophic level feed upon organism lying in trophic level prior to it.
Energy transferred to an organism lying at certain trophic level is 10% of the energy contained in an organism lying at its lower trophic level. remaining 90% of the energy is used by an organism for its internal metabolic process.
Because the lung has two bronchi, it can still function if one bronchus is blocked by a foreign object. No gas exchange will happen to the affected side, and the other lung will compensate for the loss of air. The blocked portion though can become inflamed and can lead to infection and damage.
I believe the answer must be B when considering the options.
I hope this helps, have a great day, and God Bless!
Brainliest is always appreciated :)
