Complete a Punnett square that shows a test cross for a tall pea plant (RR x rr). Place the plant to be tested at the top of the Punnett Square.

we'll use () to indicate the different boxes

      ( )   (r)    (r)

     (R)  (Rr)  (Rr)

     (R)  (Rr)  (Rr)

You will have a 2 by 2 cell for your answer.  One set of your test (rr) will go across the top as is shown and the other will be vertical (RR) as shown.  Go down the line and put the letter you see at the top in each box and then do the same going across.

      ( )   (r)   (r)

      ( )   (r)   ( )

      ( )   (r)   ( )

      ( )   (r)   (r)

     (R)  (Rr) (R)

     (R)   (r)   ( )

I tried to make this a comprehensible as possible but just draw your diagram and put the letters in the exact order as shown and then read this.  It may make more sense that way.

Explanation:

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.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.