Select all that apply. which valences have the greatest tendency to form ions? +1 -1 +2 -2 +3 -3 +4 -4

Some plants rely on the wind to reproduce an example is it’s important for plants to use the forces of nature to reproduce because 1. 1a white tuft of dandelion seeds 2a spiked burrs surrounding seeds 3a hard shell on a walnut? 2. 1b require pollination to reproduce 2b reproduce only asexually 3b cannot move about freely?

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen

Which statement describes compounds a. compounds are made of one type of atom. b. compounds cannot be represented by models. c. compounds are represented by chemical formulas. d. compounds cannot be broken down into simpler forms.