2. Bacteria can kill organisms in eutrophic lakes by Blocking out sunlight, halting the photosynthetic process in underwater plants

Reducing oxygen dissolved in the water when feeding on decaying plants and animals

Growing out of control and breathing all of the oxygen in

the lake
Initially adding excess nutrients to the lake

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

rain is the best answer