I believe the answer is C) Air Pollution
Answer:
lvl 2 - Molecules consist of atoms
lvl 3 - Cells consist of molecules
lvl 4 - Organisms consist of cells
lvl 5 - Populations consist of organisms
lvl 6 - Communities consist of populations
lvl 7 - Ecosystems consist of communities interacting with their environment
lvl 8 - The biosphere consists of all ecosystems on Earth
Explanation:
Dr. Haxton says the O-O bond is polar and the C-C bond is nonpolar. A good student would say ...
a.No, both bonds are highly polar.
b.Yes. O attracts electrons more strongly than C.
c.Right! O is electronegative, so O2 is polar.
d.Wrong again, Ralph. Both bonds are nonpolar. When two atoms of the same kind form a covalent bond, they share electrons equally because their electronegativity is the same.
e.No way. C is more electronegative than O.
Answer: d.Wrong again, Ralph. Both bonds are nonpolar. When two atoms of the same kind form a covalent bond, they share electrons equally because their electronegativity is the same.
Explanation:
Often when O and H are present in the substance at (opposite) ends (of the electronegativity scale), the polarity observed is very large, we can safely say the substance have a polar bond in it.
Mammalian fertilization comprises sperm migration through the female reproductive tract, biochemical and morphological changes to sperm, and sperm-egg interaction in the oviduct. Recent gene knockout approaches in mice have revealed that many factors previously considered important for fertilization are largely dispensable, or if they are essential, they have an unexpected function. These results indicate that what has been observed in in vitro fertilization (IVF) differs significantly from what occurs during “physiological” fertilization. This Review focuses on the advantages of studying fertilization using gene-manipulated animals and highlights an emerging molecular mechanism of mammalian fertilization.
