PONCAI`RE CONJECTURE If M is a 3-manifold with trivial fundamental group, and H_i(M)=0 for i=1,2 and =Z for i=0,3 (i. e., M has the homology groups of a 3-sphere), then M is homeomorphic to the 3-sphere.

step-by-step explanation:

because 1/3 is a fraction. we can tell because there is a divisor symbol between the 1 and the 3. if we were to add 2 fractions together, we would add the numerators, which is the number on top, but not the denominators, which is the number on the bottom

1/3+1/3=2/3

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the answer is d

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