On this page
In the spotting round of the biology practical, you name a slide, specimen or chart and back the name up with reasons. The list of what can appear is published in advance, so preparation pays off.
The CBSE Biology curriculum for 2026–27 sets the Class 12 practical at 3 hours and 30 marks, with 7 marks for spotting. It also lists what the spotting round can draw from, shown as permanent slides, micrographs, models, specimens or flash cards.
What is on the spotting list for Class 12 biology?
The 2026–27 curriculum names 11 spotting items:
Flowers adapted to pollination by wind, insects and birds.
Pollen germination on the stigma, as a permanent slide or scanning electron micrograph.
Stages of gamete development in T.S. of testis and T.S. of ovary (grasshopper or mouse).
Meiosis in onion bud cells or grasshopper testis.
T.S. of a mammalian blastula.
Mendelian inheritance using seeds of different colours or sizes.
Pedigree charts for traits such as tongue rolling, blood groups, ear lobes, widow's peak and colour blindness.
Controlled pollination: emasculation, tagging and bagging.
Disease-causing organisms such as Ascaris, Entamoeba, Plasmodium and the ringworm fungus, with a comment on the symptoms they cause.
Lichens, root nodules of legumes, and Cuscuta on its host.
Homologous and analogous organs.
Ask your teacher which of these your lab actually has.
How do you write an identification with two reasons?
Use the same three lines for every spot:
Identification: the exact name, including the view (T.S., L.S., whole mount).
Reasons: two features you can see on this slide or specimen.
Comment: one line on why it matters, where the question asks for it, such as the disease a parasite causes.
A reason is something the examiner can check by looking at the spot. "Helps in reproduction" is a function, so it proves nothing. "Long, well-exposed stamens" is a feature, so it does.
Worked example 1, a maize or grass flower:
Identification: wind-pollinated flower.
Reason 1: stamens are long and well exposed, and the flower is small with no showy petals.
Reason 2: the stigma is large and feathery, which traps airborne pollen.
These are the standard features of wind pollination: small, inconspicuous flowers, little or no nectar, light non-sticky pollen, exposed stamens and feathery stigmas.
Worked example 2, a stained blood smear:
Identification: Plasmodium, the malaria parasite, in a blood smear.
Reason 1: small ring-shaped stages sit inside red blood cells.
Reason 2: some cells hold crescent- or sausage-shaped gametocytes, typical of P. falciparum.
Comment: causes malaria. Add the symptoms from your NCERT chapter on human health and disease.
The CDC's malaria identification guide describes these ring forms and crescent-shaped gametocytes, and names Giemsa as the preferred stain.
What features identify the other common spots?
Use these as your two reasons, then check them against your NCERT textbook:
T.S. of testis: many round seminiferous tubules, lined by Sertoli cells with spermatogenic cells at different stages; Leydig cells lie next to the tubules.
T.S. of ovary: follicles at different stages, primary, secondary and tertiary, with mature ones called Graafian follicles.
Entamoeba histolytica: mature cysts have 4 nuclei, and trophozoites may contain swallowed red blood cells, though the CDC notes this is rarely seen on stained smears.
Ringworm fungus: usually Trichophyton, Microsporum or Epidermophyton; the rash is red, itchy, scaly and ring-shaped.
Root nodules: swellings on legume roots, coloured by leghaemoglobin, which is red.
Lichen: algae or cyanobacteria living in partnership with fungi, growing as a crust, flat leafy lobes or a small shrub.
For the slides you also prepare yourself, revise the features from our guides to pollen germination on a slide and the onion root tip mitosis slide. To tell a meiosis spot from mitosis, go over the stages and chromosome counts of mitosis and meiosis.
How should you practise for the spotting round?
Start two weeks before your practical date:
Make one card per spot: identification, two reasons, one comment.
Each evening, look at an image of five spots with the names covered and write all three lines from memory.
Ask your teacher for ten minutes with the lab's permanent slides, since real slides can look quite different from textbook figures.
In the last two days, go through all the cards once, out loud.
When a reason does not make sense to you, look up the idea in the Fermi Concept Library, which has a lesson for each biology concept. If you don't know where to begin, Fermi's AI tutor can work out what you already know and build a plan for the session.
Pick three spots tonight and write their cards.
