Five refugee families have arrived in our small town and their delight in our peaceful lives makes me happy that we decided to invite them.

Choose the sentence that shows correct parallel structure.

In the Walmart ecosystem, P&G: 

The greatest advancements in science in the last decade.

Top-down political initiatives rely on group mobilization to advance interests.

Technology plays a key role in the “bottom-up” approach to political power by enabling crowdsourcing of ideas.

Why does the energy density of matter scale as a−3 and the energy density of radiation scale as a−4? (Explain the physical reason – simply quoting ω for matter and radiation is not sufficient.)

WORD FORMS INSTRUCTIONS: Choose the correct word form to complete each sentence. 

Fiberglass insulation was installed when the house was built, but the previous owners of the house _________ it with natural wool.

What is a standard candle? Why is it important to observe standard candles at redshifts greater than z = 0.5 to obtain a precision measurement of q0?