Why can dinoflagellate blooms be harmful to humans?
a. dinoflagellates produce toxins that kill shellfishb. during algal blooms, dinoflagellate population densities reach very high levelsc. dinoflagellate blooms are not harmful; they are just unsightlyd. people can get paralytic shellfish poisoning during dinoflagellate blooms

Dinoflagellate is a type of neurotoxin which is found in the red-tide algae.

The answer is:

d. people can get paralytic shellfish poisoning during dinoflagellate blooms

Dinoflagellate algal blooms, during red-tide, release strong neurotoxins that can be ingested by shellfish and passed on to humans who eat the infected shellfish. The most significant public health problem that has been known to  cause this harmful algae poisoning is: Amnesic Shellfish Poisoning (ASP).

the atomic number of magnesium is 12. its nucleus must contain 12 protons and no electrons. the atomic number of an atom is determined by the number of protons.

magnesium is an electrolyte injection commonly used to treat low magnesium levels in your blood. it is also used to prevent or control seizures in women with preeclampsia or eclampsia.