What did thomas jefferson mean when he said there will never be a people who are politically ignorant and free?  

For a someone to be an individual and critical thinker they must have an education that allows for their on decision making as well as questions the decisions of others. If people are ignorant in politics then they are at the mercy of those who meet the intellectual requirement. Having political intellect allows people to think on their own. The politically educated are able to have a free mind and speak for themselves rather than relying on or conceding to others.

Manual pipetting creates a musculoskeletal load on the neck, shoulders, and upper limbs and the type of injuries that this can lead to is called repetitive stress injuries.

It’s letter b because the area of the trapezoid is 72