Decomposers are important in the food web since these break down chemical substances.
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Let me know if you want explanations :)
Natural selection is when certain environmental qualities cause a species to evolve in order to survive in the environment. Natural selection is a specific part of that, when some of the variations of the species die off because they can't survive, then the ones who survive live to create more living babies with the qualities that allow them to survive in the environment.
If both of those sexual partners are faithful to each other, and only have sexual relations with one another, then there isn't a high probability that either of them is going to get HIV. If they want to be sure, they should use protection, such as condoms, to prevent getting HIV through body fluids. And they should always be honest with each other in case one of them has that disease.
Answer: No, because the lysosome and the cell, membrane are needed.
If cells didn't have a membrane, the cell would just melt everywhere. If we didn't have lysosomes, there would be a lot of toxins in the cells.
Hope this helps :)
