How is carbonic acid responsible for the formation of some caves? asap

An incident ray through the focal point of a spherical mirror will: reflect through the center of curvature. reflect back through the focal point. reflect parallel to the principle axis. reflect the same direction as the incident ray.

You can decrease the resistance of a length of wire by

Which missing item would complete this alpha decay reaction ? > 228/88ra + 4/2he a.224/96 rn b. 232/90 th c. 230/92 u d. 235/92 u