The immune system's goal is to protect the body against invaders either from without, such as microbes, or from within, such as cancers and different types of neoplastic transformation.

My go-to prebikini flat-ab move is the plank, all different types.

Different times need different types of leadership.

There is an urgent need for a protective Ebola vaccine, and it is important to establish that a vaccine is safe and spurs the immune system to react in a way necessary to protect against infection.

I get to partner up with all different types of opportunities.

We do need different types of propulsion to get to Mars. I wrote one of the first Ph.D. theses on that in the 1960s.