1.
(a)
(i) Helps in code reusability.
(ii) Improves code readability.

(b)Yes.
Primarily efficiency. 

2.
a=1, b=2

3.
(a)
int is_Palindrome(char s[])
{
  int i;

  for(i=0; i<(strlen(s)/2); i++)
    {
      if(s[i]!=s[strlen(s)-i-1])
        return 0;
    }

  return 1;

}


(b)
int is_Palindrome_rec(char s[], int start)
{
  if(start>=strlen(s)/2)
    return 1;

  if(s[start]!=s[strlen(s)-i-1])
    return 0;
  else 
    return is_Palindrome_rec(s,start+1);
}

int is_Palindrome(char s[])
{
  return is_Palindrome_rec(s,0);
}


4
(a)
int max_position(float a[],int start,int end)
{
        int i,pos;
        float max;
        if(start>end)
        {
                return -1;
        }
        max = a[start];
        pos = start;
        for(i = start ; i <= end ; i++)
        {
                if(max < a[i])
                {
                        max = a[i];
                        pos = i;
                }
        }
        return pos;

}

(b)
void selection_sort(float a[],int size)
{
        int i,pos;
        float temp;
        for(i = size - 1 ; i >= 0 ; i--)
        {
                pos = max_position(a,0,i);
                temp = a[pos];
                a[pos] = a[i];
                a[i] = temp;
        }

}


5.
int subsequence(char s1[],char s2[],char s3[])
{
        int i,j,size;

        
        size = strlen(s1);
        for(i = 0 ; i < size ; i++)
        {
                s3[i]='0';
        }
        s3[size] = '\0';


        i = 0;
        j = 0;
        while(s2[i] != '\0')
        {
                if(s1[j] == '\0')                                
                {
                        return 0;
                }
                if(s1[j] == s2[i])
                {
                        i++;
                        s3[j] = '1';
                }
                j++;
        
        }
        return 1;

}