PLEASE HELP :(( which of the following are necessary for successful chemical reaction to occur?  1. correct orientation of particles when they collide
2. Particle collisions
3. Sufficient energy when particles collide

A. 1 only
B. 1 and 2 only
C. 2 & 3 only
D. 1, 2, and 3

In sexual reproducing animals once fertilization of the egg takes place, the exists as a single cell until cell division begins. a) egg b) larva c) sperm d) zygote

Any sound above what db can cause hearing loss in human beings

7. describe two strategies that parents can use to cope with stress. 8. describe the three types of childcare available to families. 9. what can parents do to be more involved in their children's education at home and at school? 10. which factors should a parent consider when choosing a childcare option?