Polar<span> molecules
water molecules have a weak, partial negative charge at one region of the molecule (the oxygen atom in water) and a partial positive charge elsewhere (the </span>hydrogen<span> atoms in water).The force of attraction is called a </span>hydrogen bond<span>.</span>
I think it's A. They have a cell membrane.
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Explanation:
Tornado is damaging during a thunderstorm;)
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.
Two intermediates of the sterol biosynthesis pathway, isopentenyl diphosphate and dimethylallyl diphosphate, are used by archaea in the biosynthesis of isoprenoids. Isoprenoids are organic compounds <span> which play widely varying roles in the physiological processes of plants and animals.</span>
