Download App

Human Reproduction — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYHuman Reproduction5 Marks
Question
When and how does placenta develop in human female?
✓

Answer

Placenta develops after implantation of embryo in human female in the uterus. After implantation, finger-like projections called chorionic villi are surrounded by the uterine tissue and maternal blood. The chorionic villi and uterine tissue become interdigitated with each other and together form a structural and functional unit between developing embryo and maternal body called placenta.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Long Answer Type Questions [5M]" from Human Reproduction→Human Reproduction — all question types→BIOLOGY STD 12 Science question papers→Bihar Board STD 12 Science question papers→Bihar Board question paper generator→

Similar questions

What are bacterial phages? Describe their structure in detail.
→
Give the term/ reason:
Role of oxytocin during expulsion of the baby out of uterus.
→
Differentiate between:
a. hypocotyol and epicotyl
b. coleoptile and coleorrhiza
c. integument and testa
d. perisperm and pericarp
→
Answer the following questions:
Explain the hormonal regulation of the process of spermatogenesis in humans.
→
How does replication of the long DNA molecule occur? Explain the process.

OR

Explain the process of DNA replication with the help of a replicating fork.

→
Which vectors can be used to clone a fragment of DNA with the following lengths?
  1. 4Kb
  2. 35Kb
  3. 20Kb
  4. 250Kb
→
A bright student of class XI, under peer pressure started taking drugs. He started neglecting studies, misbehaving with parents and friends in school. The principal of school counselled him, but it had no effect. His parents took him to a rehabilitation center. After a few months, he came back recovered.
  1. What is drug abuse?
  2. Name some commonly abused drugs and their source.
  3. What should be the attitude of his parents after his return?
  4. What values did the principal reflect through his initiative?
→
  1. Represent diagrammatically three kinds of age-pyramids for human populations.
  2. How does an age pyramid for human population at given point of time helps the policymakers in planning for future?
→
Describe the difference between the structures of a dicot embryo and monocot embryo. Also draw LS of monocot and dicot seeds.
→
Describe the structure of human sperm.###Describe the structure of sperm with suitable diagram. Also define supermatogenesis.
→