The shape of DNA is described as a double helix. Click all that apply to the description of DNA. a. DNA is made from a single strand of nitrogenous bases.
b. A double helix resembles a “twisted ladder”
c. The “backbone” of the ladder is made up of alternating sugar and phosphate groups
d. The “rungs” of the ladder are made up of the bases joined by hydrogen bonds

The serengeti plains are part of the african savanna ecosystem and are home to a variety of different species of plants and animals. the serengeti plains experience a seven-month period of seasonal drought each year, during which the ecosystem receives only four inches of rain and the availability of some resources becomes very scarce. which type of limiting factors does the seasonal drought in the serengeti plains affect?