Question

Chemical bonds
a. are always ionic.
b. combine compounds to form elements.
c. are always covalent.
d. hold atoms together to form compounds.

. A pyramid of numbers differs from an ecological pyramid because it
a. shows the amount of energy within each trophic level.
b. displays the number of organisms at each trophic level.
c. is organized by trophic levels, while an ecological pyramid isn't.
d. attempts to describe a food chain or food web.

Answer 1

Chemical bonds hold atoms together to form compounds through the sharing of electrons or the transferring of electrons. 
Bio is not my strongest subject, but I am pretty sure that a pyramid of numbers differs from an ecological pyramid because it displays the number of organisms at each trophic level

Answer 2

D. displays the number of organisms at each trophic level.

Hope I was helpful :)