NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF EDUCATION
JULY 2017 EXAMINATION

COURSE CODE: SED 421 (2 units)

COURSE TITLE: CYCLES IN NATURE BIOLOGICAL CYCLE

TIME:                 2 HOURS

INSTRUCTION: ANSWER QUESTION ONE(1) AND ANY OTHER TWO(2) QUESTIONS. 

1. (a)      Explain the relationship between photosynthesis and respiration in connection with carbon cycle.                                                         (10 marks)

          (b)      Discuss FOUR steps through which Carnot cycle act as a heat engine.

.  (12 marks)

(c ) Enumerate EIGHT  human activities that change the water cycle (8 marks)

2.        (a)      Differentiate  between Diesel Cycle and Water Cycle.                     (7 marks)

          (b)      Write short notes on the following  terms:

(i)     Nitrogen fixation       

(ii)    Nitrification       

(iii)  Denitrification        

(iv)  Ammonification    ( 8marks)

3.        (a)      What is Tectonic Cycle?  Describe FOUR stages in the Tectonic Development..   (11 marks)

          (b)      List FOUR features of plate tectonics.                                   (4 marks)

4.        (a)      Describe the activities that occur in the following stages of erosion in an Arid climate?

1.  Initial stage                                
2. (ii)Mature stage
3. (iii)     Beginning of old age

 (10 marks)

(b)      List FIVE factors that regulate protein-protein interactions. (5 marks)