Gradual changes in the frequency of diseases over long periods are known as SECULAR TIME TRENDS. For example, the rate of mortality in USA due to coronary heart diseases over a period of time. Onset of puberty in girls is also a secular time trend.
Secular time trend is also referred as Secular Variation and Secular Drift.
Answer:
Motor nerves
Explanation:
Pulling the leg quickly from the sharp object is an example of reflex action. It includes sensory receptors, sensory neurons, interneurons, the control center (spinal cord), motor neurons and effector.
As soon as she steps on the glass piece, the receptors present in the skin of her foot sole sense it and send the information to the control center via sensory neurons. The spinal cord commands the muscles of the effector organ (leg) via motor neurons to move to step away from the glass piece.
Answer:
a. all tall
Explanation:
If genotypically one of the parents is homozygous dominant and another one is heterozygous for plant height then phenotypically all their progeny will be tall.
Let us suppose, 'T' represents dominant allele and 't' represents recessive allele. Then the genotype of one parent who is homozygous dominant will be TT and genotype of another parent who is heterozygous will be Tt.
The cross is depicted in the attachment.
Here it may also be noted that genotypically two of the progeny will be homozygous dominant while two of the progeny will be heterozygous but phenotypically all the progeny will be 'tall'.