The specific term to characterized the downward
growth of roots in response to earth’s gravity pull is called positive geotropism.
The word geotropism was derived from two words, “geo” which means ground and “tropism”
which describes a plant movement elicited by a gravitational stimulus.
In addition, the root cap makes the roots turn
downward as they grow for they have specialized cells with sensors called
statoliths that settle to the lowermost part of the root cap in response to the
pull of gravity and help the cell multiply more rapidly in a downward direction.
<span> </span>
Answer:
Allopatric speciation occurs due to the geographical isolation between individuals of the same species. The geographical isolation can be due to canyon development, mountain formation, migration, etc.
The geographical isolation gives different environmental condition to the separated population of same species to live which allow these two population to evolve differently and evolve in different species.
So when two population becomes different species and not able to interbreed with each other when give opportunity then the allopatric speciation between the two populations becomes complete.
Answer:
a. Heterozygous individuals may pass on their copy of the disease-causing allele to offspring.
Explanation:
Tay-Sachs, which is a recessive lethal disease ---- Let say the recessive lethal diseases is s
∴ it only results when an individual posses two copies of the diseases-causing allele i.e two copies of the disease will be ss.
Now, when two hetrozygous individuals crossed , it is obvious that each can pass on their copy of the disease-causing allele to the offspring.
Let show an illustration for the above statement.
Let the heterozygous individual be Ts, if Ts cross with another Ts;
we will have:
Ts × Ts
T s
T TT Ts
s Ts ss
the offspring are TT,Ts,Ts,ss
We can now see how the Heterozygous individuals pass on their copy of the disease-causing allele to the offspring (Ts).
