Question

Why did the United States ban the use of DDT?
It began mutating.
It became too costly to continue its use.
Its risks outweighed the benefits.
It was no longer effective.

Katie wants to make ball-and-stick models of the four macromolecules. She has colored balls for each of the elements in these molecules, including the following.

red: hydrogen
black: carbon
purple: oxygen
green: nitrogen

In which macromolecule will she use the black, red, and purple balls in a ratio of 1:2:1?
carbohydrates
lipids
nucleic acids
proteins

Look at the picture below.

mc020-1.jpg

What macromolecules make up most of the structure that is shown?
carbohydrates
lipids
nucleic acids
proteins

Which source is the most reliable?
a report published on Wikipedia
an article evaluated by other scientists
a blog about plant growth
an advertisement about weight loss

Which inheritance pattern results when parents with pure traits are crossed and the resulting offspring have traits that appear to be a blend of the parents' traits?
incomplete dominance
codominance
Mendelian inheritance
polygenic inheritance

Answer 1

1) Its risks outweighed the benefits.
(DDT was banned because of environmental and health harms and bioaccumulation.)

2) Carbohydrates.
(Monosaccharides have an empirical ratio C:H:O of 1:2:1.)

3) Lipids.
(The image likely shows a phospholipid bilayer — membranes are made mostly of lipids.)

4) An article evaluated by other scientists.
(Peer-reviewed articles are the most reliable source listed.)

5) Incomplete dominance.
(Offspring show a blended intermediate phenotype when parents with pure traits are crossed.)