Question

A very small tilt in Earth’s axis would likely cause ____.

Answer 1

If the Earth's axis were closer to "straight up and down" than
the present 23.5°, then . . .

-- The areas around the north and south poles where the sun
can be up or down for more than 24 hours would be smaller.

-- The "Tropic Zone", between the Tropic of Cancer and the
Tropic of Capricorn, where it's possible for the sun to be
directly overhead, would be narrower.

-- There would be less difference, everywhere, between the
lengths of daylight on the "longest day" and the "shortest day"
of the year.

-- The seasons would be less extreme everywhere.  There would
be less difference, everywhere, between the coldest part of the
Winter and the warmest part of the Summer.

Answer 2

A very small tilt in Earth’s axis would likely cause  small seasonal variations.