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:
True
Explanation:
Animals can be categorized into 3 based on body symmetry
- <em>Those without any body symmetry (asymmetrical)</em>
- <em>Those with bilateral body symmetry (bilateria)</em>
- <em>Those with radial body symmetry (Radiata)</em>
Animals can be categorized into 2 based on number of embryonic germ layer;
- <em>Those with two layers - endoderm and ectoderm (diplobastic)</em>
- <em>Those with three layers - mesoderm in addition to ectoderm and endoderm (triploblastic)</em>
Animals can be categorized based on presence/absence of body cavity or coelom;
- <em>No body cavity - acoelomates</em>
- <em>False body cavity - pseudocoelomates</em>
- <em>True body cavity - coelomates</em>
Animals can be categorized into 2 based on characteristics of embryonic development;
- <em>Deuterostomes</em>
- <em>Protosomes</em>
I've checked all the options and I think that the right answer looks like this: Mollusks have highly developed olfactory receptors.