Which of the following is NOT a specific aspect of disposition that is of primary importance?

Heavy metals typically reside in bone for decades.

The persistence of DDT in the body is related to its lipophilic nature.

Which exposure pathway has the fastest uptake in the human body?

A fish is exposed to a water environment that has concentration of 100ug/L of toxicant A for 2 months. After that time period, the fish is sacrificed and found to have a calculated BCF of 0.5. This indicates _____.

Please follow these instructions carefully, as failure to follow them will result in a penalty. (i) Download the Exam template from the class website and use that to write your solutions.  (ii) The solutions to each problem should be in the space specially assigned to them. (iii) When scanning your solutions into a pdf file, each page must be scanned as a separate page and the entire exam as one pdf file. (iv) You have 135 minutes to complete the exam, including the time to scan the exam and upload it as a pdf file to Proctorio   I.  Find all solutions to  the system of equations     x_1+ 3x_2+x_3+x_4=3   2x_1-2x_2+x_3+2x_4=8 3x_1+x_2+2x_3-x_4=-1                     (20 points) II.  Let A denote the coefficient matrix for the system of equations given in I.  i) Find a basis for the Column space of A.  (10 points) ii) Find a basis for the Row space of   (5 points) iii) Find a basis for the Null space of A (10 points) iv) What is the rank of A? What is the nullity of A? (5 points) III. Solve the matrix equation A.x=b, where A= ,  x= and b= by first finding the inverse of the matrix A.(25 points)   IV.  Write the matrix A in III as a product of elementary matrices. (25 points)

  Let A= .  1. Find all the eigenvalues of A.   (12 points) 2. Find the corresponding eigen vectors.   (12 points) 3. Is A nonsingular, that is, does A have an inverse? Answer this just using the knowledge of the eigen values. Give reasons for your answer. (6 points)  

I.  (i) Given vectors v_1= , and v_2 =,  determine their span as a plane in 3-space.  (10 points)  (ii) Is the vector x =  in the span of v_1 and v_2? Give reasons for your answer. (5 points) II.  Given the matrix A= ,  (i) find an echelon form for it. (5 points)     (ii) Determine the null-space of A, using the echelon form in (i).  (5 points)     (iii) Determine a basis for the null-space of A. (5 points)

Consider the system of linear equations: x_1+3x_2+x_3+x_4=3 2x_1-2x_2+ x_3+2x_4=8 3x_1+ x_2+2x_3 -x_4=-1. I.  (a) Write the corresponding augmented matrix.  (b) Do suitable row operations so that first column is all zero except for the  entry in the first row.       (3 points each).   II. (a) Complete computing an echelon form for the above matrix.  (8 points)       (b) Find all possible solutions .   (4 points) (c) How many solutions are there? Which are the basic variables and which are the free variables, if any? (2 points) III. Given the matrix A= ,  find A^{-1}. (10 points)

I.  (i) Given vectors v_1= , and v_2 =,  determine their span as a plane in 3-space.  (10 points)  (ii) Is the vector x = in the span of v_1 and v_2? Give reasons for your answer. (5 points) II.  Given the matrix A= ,  (i) find an echelon form for it. (5 points)     (ii) Determine the null-space of A, using the echelon form in (i).  (5 points)     (iii) Determine a basis for the null-space of A. (5 points)