MATLAB using for loops and if else if statements

Data: You may load the data into MATLAB with the command load toxic.csv. The data will then be in an array called toxic. The column information represents:

Column 1: Year AD

Column 2: Cadmium (nanograms per gram)

Column 3: Lead (nanograms per gram)

Column 4: Thallium (nanograms per gram)

Section 2: Repetition Structures and Conditional Blocks

Allowed Syntax:

Complete the following (1) WITH the use of for loops and conditional blocks [i.e. if-elseifelse-end]; (2) you may NOT use any syntax requiring the dot operator; (3) you may use relational operators on scalars but you may NOT use them on arrays. (Relational operators include: <, >, <=, >=, ==, ~=) (4) You may reuse the years that were found using the find function in Section1

1. How many years during the period of this data set have a lead concentration greater than 0.2 ng/g?

2. For what percentage of the years during the 1800s (1800-1899) is the lead concentration greater than 0.01 ng/g?

3. What is the most recent year during which lead is greater than 100 times the concentration of cadmium? What is the concentration of Pb that year?

4. For which year during the 1900s (1900-1999) did cadmium contribute its largest fraction to the total heavy metal concentration (i.e., year with largest Cd/(Pb+Cd+Th))? What is that value? (hint: help max)

5. [Up to 2pt bonus] During which decades (i.e, 1900-1909, 1910-1919, etc.) of the 1900s did lead concentration exceed 0.3 (ng/g)?

I need help with problems 1-4 if you could provide the solution in MATLAB script file that would be helpful thanks.