Soil erosion is defined as the wearing away of topsoil. Topsoil is the top layer of soil and is the most fertile because it contains the most organic, nutrient-rich materials. Therefore, this is the layer that farmers want to protect for growing their crops and ranchers want to protect for growing grasses for their cattle to graze on.
<span>Charles Darwin theory is theory of biological </span>evolution, that explains how modern organisms evolved over long periods of time through descent from common ancestors. Evolution is the process of change over time and Darwin explains in his theory the changes in humans over time and <span>shows how the living world is constantly changing.</span> This is the reason why cientists refer to charles darwin’s ideas about evolution as the theory of evolution.
A hydrometer is an instrument that measures the specific gravity (relative density) of liquids. The ratio of the density of the liquid to the density of water. A hydrometer is usually made of glass, and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float
Answer:
I wasn't quite sure what virus you were referring to in your question, but here's a general answer: Viruses use their host cells' machinery to replicate themselves.
If they are a specific type of virus known as a retrovirus, they have the ability to use the host cells' enzymes to change the RNA contained within the virus into DNA (via some type of replication I suppose).
In other cases, if they contain DNA instead of RNA (that is, the virus), they can use the host cell's machinery to create RNA via enzymes involved in transcription and/or they can incorporate that DNA into the host cell's DNA. This is part of a type of viral replication cycle known as the lysogenic cycle.
In another type of viral replication cycle known as the lytic cycle, the virus simply has itself and its genome duplicated until the host cell bursts, releasing the viral material. Here, again, the virus uses the host cell's machinery to replicate itself.
A and C
They both can be compared to present or past objects to show how they have changed or evolved over time
