Earth´s northern hemisphere generally experiences warmer temperatures in July than it does in January. which statement explains why?

Do not see any statements to choose from but here is what the questioner should be looking for, hopefully.

In July the Northern Hemisphere is tilted toward the Sun.  Daylight hours are longer (June 2x is the Summer Solstice).  Cold Arctic Jet stream is pushed back up towards polar cap.  Dark soil, trees etc. absorb and retain heat overnight.

In January the earth is tilted the opposite, it is winter in Northern hemisphere and summer in southern hemisphere.  Cold Arctic jet stream is often sweeping down through northern hemisphere.  Talking -30 and below at times in some locales.

Explanation:

Answering this question in mid-December from the northern hemisphere:

Our daylight period is only around 8 hours.  

Very depressing I might add...  SAD  Seasonal Adjustment Disorder

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.