  The orbital evolution of Jupiter-family comets (JFCs), resonant asteroids,
and asteroidal, trans-Neptunian, and cometary dust particles under the
gravitational influence of planets was integrated. For dust particles we also
considered radiation pressure, Poynting-Robertson drag, and solar wind drag.
The probability of a collision of one former JFC with a terrestrial planet can
be greater than analogous total probability for thousands other JFCs. If those
former JFCs that got near-Earth object (NEO) orbits for millions of years
didn't disintegrate during this time, there could be many extinct comets among
NEOs. The maximum probability of a collision of an asteroidal or cometary dust
particle with the Earth during its lifetime was for diameter $d$$\sim$100
microns. At $d$$<$10 micron, the collision probability of a trans-Neptunian
particle with the Earth during a lifetime of the particle was less than that
for an asteroidal particle by only a factor of several.
