Why is it difficult to classify protists? Select three options.

There are many varying characteristics and exceptions to each type of protist.
They have been previously categorized based on what they are not.
They are all eukaryotes composed of one or more cells that contain nuclei.
There are no exceptions to the characteristics of each type of protist.
They are microscopic and therefore too small to study accurately.
Recent studies show that protists have not descended from one common ancestor.

Please help me, I have a bad grade in science so far : (

According to the loco mass the mass of reactants and products

During an investigation of an xss attack, the investigator comes across the term "[a-za-z0-9\%]+" in analyzed evidence details. what is the expression used for?

How do temperature and salinity affect deepwater currents? they create changes in wind direction, moving denser water in the same direction as the wind and causing the deepwater circulation patterns found in the ocean. as temperatures and salinity levels of water increase, the water rises to the surface where it creates currents as it moves to colder regions. they create density differences that cause dense deepwater currents to flow toward the equator where they displace less dense, warmer water above them. they equalize the forces on undersea currents caused by the coriolis effect as they replace more dense water with less dense water.