I NEED HELP ASAP! Which of the following is true of variation? Select one:
a.
It is necessary for natural selection.
b.
It exists in almost all populations.
c.
It is caused by mutations and sexual reproduction.
d.
All of the choices are correct.

Step 1 review the imaginary strand of dna below. note the complementary base pairs. a g c a a t c c g t c t t g g t c g t t a g g c a g a a c c step 2 to begin replicating this strand of dna, draw the two sides of the strand separating. step 3 now, draw the free-floating bases linking up with the separate sides. remember to follow the rules of complementary base pairing. step 4 draw the two resulting dna strands.

The bacteria inside a tube worm would be analogous to what organism in the ocean ecosystem near the waters surface? a. photosynthetic algae b. shrimp c. clown fish d. parasitic lamprey

Which could be a pathway of food through an ecosystem