Which of the following poses the greatest risk for species extinction?
a.
expansion of human cities
b.
increased levels of pollution
c.
intense hurricane activity
d.
uv radiation and the hole in the ozone layer

Which of the following is a main difference in cell structure between an onion cell and a human cheek cell? a. an onion cell contains one nucleus, whereas a human cheek cell contains two nuclei. b. an onion cell has a cell wall. c. a human cheek cell contains chloroplasts. d. there is no difference between an onion cell and a human cheek cell. you for your.

Select the correct answer. a chestnut-colored horse mates with a white-colored horse to produce a brown and white spotted offspring. what is the type of inheritance pattern?

Most of the carbon on earth is stored in the form of