Question

reread the paragraph from the passage
the students heartbeats and blood flow were measured during the
experiment. the researchers discovered that the students arteries
expanded, letting more blood flow to all the bodys tissues. according
to seery, more blood primes us for movement. it supplies us with
extra energy, making us more alert and able to deal with challenges.
this shows that the students experienced the situation as a positive
challenge.
it refer to? complete the sentence.
supplies us with extra energy, making us more alert and able to
deal with challenges.

Explanation:

The text clearly states "According to Seery, more blood primes us for movement. It supplies us with extra energy...". Here, the pronoun "It" refers back to the immediately - preceding noun phrase "more blood".

Answer:

More blood supplies us with extra energy, making us more alert and able to deal with challenges.