Question 1
which of the following is not a characteristic that defines a species?
a. it has common physical traits
b. it can interbreed
c. its offspring can reproduce

question 2
two different species can breed and produce offspring.

a. true
b. false

question 3
which of the following is a type of postzygotic barrier?

a. behavior isolation
b. temporal isolation
c. habitat isolation
d. production of weak offspring

question 4
sympatric speciation involves geographic barriers while allopatric species does not.

a. true
b. false

question 5
isolation itself is a mechanism for evolution.

a. true
b. false

1

A. It has common physical traits

Explanation:

A species is a group of organisms having many similar characteristics which can freely interbreed to give rise to fertile offsprings.

Members of a given species do not have to be physically same.

The key words here are;

2

A. True

Explanation:

Organisms from two different species can breed and reproduce offsprings.

Provided this two organisms come from the same genus.  

The resulting offspring is usually sterile to avoid extensive inbreeding if the given organisms

Through this gene flow is prevented.

The offsprings display traits similar to the parents.

3

D. Production of weak offspring

Explanation:

Postzygotic reproductive barriers occur after a zygote is formed in order to, either reduce viability or to reduce the hybrid's life-span

Production of a weak offspring, for example a sterile offspring prevents further reproduction of the hybrid.

Since the hybrids can not give birth to new offsprings, genetic mix up is prevented thereby discouraging gene related complications in the resultant offsprings.

4

B. False

Explanation:

The explanation of the two is the direct opposite of each.

Sympatric speciation involves the evolution of a new species from a surviving ancestor, in this, both continue to inhabit the same geographical area.

Allopatric speciation on the other hand is the evolution of species caused by geographical isolation of a population's species.

5

A. True

Explanation:

Isolation is a mechanism of evolution.

Reproductive isolation for instance are evolutionary mechanisms  involved and are critical in speciation.

Isolation works in the sense that;  

When two members of different species are isolated, they are incapacitated in the production of an offspring.

Isolation also might work to ensure that in case of reproduction, the offspring is either weak or sterile.

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides

not sure if this is what you'r looking for eubacteria and archaebacteria