Answer:
Covalent bonds form when two atoms share valence electrons,
while Van der Waals forces cause an attraction between nonpolar
molecules
Explanation:
A covalent bond is said to be formed when two atoms of the same or different elements share electrons. In an ordinary covalent bond, each bonding atom contributes one valence electron while in a dative covalent bond only one of the bonding atoms provides the shared pair of electrons.
Van Der Waals forces is the major intermolecular interaction between non polar compounds. Van Der Waals forces " are caused by correlations in the fluctuating polarizations of nearby particles"(Wikipedia).
Answer:

Explanation:
Straight wings are dominant over curved wings
Let Straight wings : H
curved wings : t
smooth eyes are dominant to sparkling eyes
let smooth eyes = H
spark ling eyes = t
tan body is dominant to ebony body color.
Again; Let tan body color be H
Let ebony color be t
If flies that are heterozygous for all three traits are crossed;
we have HtHtHt × HtHtHt
Then the selected trihybrid traits for the cross will be (HHH,HHt, HtH, Htt, tHH, tHt, ttH, ttt)
We will realize that from the punnet square in the diagram below, the proportion of the offspring would you expect to be heterozygous for all three traits (i.e HtHtHt) is asterisk in the punnet square and will be 
= 
1. They are easy to raise.
2. Have many offspring during per mating.
3. It can fertilize itself.
4. It has varieties in genotype that is easy observable.
5. It has phenotype that is also easy observable.
Try looking this up through quizlet! i found one called “plant responses “ that may help you