Answer:
Option A
Explanation:
Thyroid is primarily caused by lack of iodine but there are other reasons as well that lead to increased size of the thyroid gland. Some of these reason is
a) over- or underproduction of thyroid hormones
b) Nodules in the glans
Some times, due to overstimulation immune system itself attack the thyroid gland thereby producing excess thyroxine and hence causing the thyroid to swell
Thus, Option A is correct
Answer:
Explanation:
This is because the sieve plate interconnected like that help in exchange of substances or transport of substances between element cell and it act as a barrier to prevent the sap from been loss when phloem is damaged or cut. The sieve plates form the sieve tube which is the conducting element of the phloem. It is formed from series of elongated cells that are interconnected by perforations in their walls.
Answer:
Cartilage rings of trachea have protective role
Explanation:
Trachea is a tube, part of the respiratory system, which allows the passage of the air: from larynx to lungs (primary bronchi). It is enveloped with cartilage rings that prevent collapse of the trachea when there is no air. The cartilage "rings" are C-shaped, except one full ring-shaped - the cricoid cartilage which attaches trachea to the larynx.
Answer:
Explanation:
First-generation (F1) progeny only showed the dominant traits, but recessive traits reappeared in the self-pollinated second-generation (F2) plants in a 3:1 ratio of dominant to recessive traits. Mendel then crossed these pure-breeding lines of plants and recorded the traits of the hybrid progeny
