Answer:
The answer is b.) and d.)
Explanation:
The options to reduce the background noise in magneto-medicine are given as follows:
a.) Orienting the heart parallel to the Earth's field
- This will have no significant effect on the measurements.
b.) Taking the difference of two nearby sensor measurements (gradiometer).
-This answer is TRUE.
c.) Placing the heart in a perpendicular fashion to the Earth's magnetic field.
_ This answer also will not have any significant effect on measurements.
d.) Using physical means to shield environmental fields.
- This answer is TRUE.