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.
The right answer is HEPA filter.
A HEPA filter (High Efficiency on Particles Air) can filter up to 99.97% of 0.3μ aerial particles.
These filters are used to clean the air and retain suspended particles (dust, pollen, bacteria etc.) and other particles that can cause respiratory allergy in sensitive subjects.
They are very used in sterile rooms
Answer:
<h2>Source of Light in Universe</h2>
<h3>Although the Sun doesn't light up the other stars, it does provide the daylight here on Earth; and the moon and planets we see are illuminated by that same sunlight. All stars produce light (and other kinds of energy) through nuclear reactions, using the energy stored in the tiny nucleus at the center of atoms.</h3>
Explanation:
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<em><u>THANKS</u></em><em><u>❤</u></em><em><u>❤</u></em></h2>
Answer:Evaporation Evaporation is simply the process by which liquid turns into a gas. Water (a liquid) turns into vapor (a gas) when heat energy is applied to raise its temperature to 100°C (212°F). Water in the liquid state is a compound, and the heat breaks up the bonds into water molecules, which is gaseous.
Explanation:
