B. One
because an independent variable is something you change. So in a scientific experiment you only change one thing. If you happen to change more than one thing then the test becomes unfair therefore you should repeat and make sure that only one thing is changed this time.
Answer:
A gene is a stretch of DNA or RNA that determines a certain trait. Genes mutate and can take two or more alternative forms; an allele is one of these forms of a gene. For example, the gene for eye color has several variations (alleles) such as an allele for blue eye color or an allele for brown eyes.
Explanation:
Answer:
All colour except which is already present in the body.
Explanation:
The plant leaf has green colour so the plant absorb all the colour except green. The presence of green colour causes reflection of green colour so that's why we can see the green colour of the leaves. Every material or substance have a specific colour which can be seen when they absorb all light except the colour which is already present in it so we can say that that colour is not absorbed by the body which is already present in it.
Answer:
C. development of vascular tissue for bulk flow
Explanation: