Unicellular organisms excrete waste by a contractile vacuole. A vacuole is membrane-enveloped organelle in a cell that is found in lots of microorganism. It expands, filling with water then contracts, removing all of its contents to the exterior of the cell.
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.
Answer:
Cane toads were introduced intentionally in Australia in 1935 to combat cane beetles in the sugar cane crop fields. These toads exhibit higher feeding capacity. These can feed not only cane beetles but other insects which affecting agricultural yields. They are poisonous in nature, they kill any insect after ingestion. Therefore, they are useful biological insecticide which provides crops resistance against insects.
The correct answer is C. Gardeners choose which plants they let reproduced based on the plant traits.
Explanation:
In general, selective breeding involves the intervention of humans in the reproduction of species, this includes mainly plant and animal species. Moreover, in selective breeding, humans choose which specific species or individuals reproduce to favor certain traits. For example, a farmer might allow only the biggest cows to reproduce because this will lead to bigger calves. In this context, the option that shows selective breeding is C because this shows the intervention of humans in reproduction by selecting the individuals that will reproduce.
