Despite their seemingly simple anatomy and radial symmetry Sea urchins and sea star are a type of deuterostome, closely related to the chordates.
What are the characteristics of deuterostome?
Animals classified as deuterostomes share a common embryonic development.
The first opening during development known as the blastopore changes to the anus in deuterostomes while the mouth changes in protostomes.
They have a coelom, which forms as a result of enterocele (coelom from the digestive tract).
These creatures include the following,
- Chordata,
- Echinodermata,
- Hemichordata.
Hence the correct answer is Deuterostome.
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Answer:
b. It is a testable statement.
Explanation:
Answer:
Any step of gene expression may be modulated, from the DNA-RNA transcription step to post-translational modification of a protein.
Answer:
for number 2 its mosses or lichens
Answer:
Gametogenesis is the formation of gametes, in males it is referred as spermatogenesis and in females it is called oogenesis.
Explanation:
Differences between spermatogenesis and oogenesis:
1. Spermatogenesis is formation of sperms from spermatogonia and oogenesis is formation of ova from oogonium.
2. Location: Production of sperms occur in testis and production of ova occurs in ovaries.
3. In males, spermatogenesis begins at puberty and its a continuous process till death whereas in females, oogenesis begins at fetal stages, it halts and rest of the process occurs after puberty till menopause.
4. Primary spermatocyte undergoes meiosis-I to form two secondary spermatocytes, whereas primary oocyte undergoes to M-I to form a single secondary oocyte with a polar body.
5. Meiosis-II results in the formation of 4 spermatids or spermatozoa, in females however M-II results in only one ovum and second polar body formation.
6. Overall we can say that single spermatogonium forms 4 spermatids whereas single oogonium forms only 1 ovum.
7. Sperms are motile where as ovum in non-motile.