Use the drop-down menus to complete the statements. All of the chromosomes line up along the middle of the cell during .

The nuclear membrane disappears during .

DNA condenses to form chromosomes during

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.