When does a zygote become a multicellular creature?
a. at fertilization
b. when cleavage begins
c. when organs begin to form
d. when the heart begins beating
e. at birth
B
You might also like to view...
Which of the following is the correct sequence during the alternation of generations life cycle in a flowering plant?
A) sporophyte ? meiosis ? gametophyte ? gametes ? fertilization ? diploid zygote B) sporophyte ? mitosis ? gametophyte ? meiosis ? sporophyte C) haploid gametophyte ? gametes ? meiosis ? fertilization ? diploid sporophyte D) sporophyte ? spores ? meiosis ? gametophyte ? gametes E) haploid sporophyte ? spores ? fertilization ? diploid gametophyte
While conducting an experiment, you realize that a competitive inhibitor was interfering with your reaction. How could you overcome this problem?
A. Add a non-competitive inhibitor to the reaction. B. Add a cofactor to the reaction. C. Increase the concentration of the correct substrate in the reaction. D. Add an allosteric activator to the reaction.
We expect the fossil record to be incomplete for all of the following reasons EXCEPT:
A. All biomolecules, including lipids and pigment molecules, decay immediately after death. B. Fossilization requires burial in sediment. C. Sediments accumulate irregularly. D. Organisms with hard parts tend to fossilize more readily than soft-bodied organisms. E. Under normal conditions, organisms are broken down by biological and physical processes.
Which of the following is true for the cell shown
above? a. They patrol the body looking for invaders. b. They present antigens to other WBC’s. c. They specifically interact with T-helper cells. d. They mature only after they encounter damaged tissue. e. All of these are true.