Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

In a case of polyembryony, if an embryo develops from the synergid and another from the nucellus, which is haploid and which is diploid?

Which hormone induces the rupturing of graafian follicle during ovulation from female's ovary?

How does the strength and weakness of linkage depend on linked genes?

Name the interaction in each of the following:

1. Cuckoo lays her eggs in the crow's nest.
2. Orchid grows on a mango tree.
3. Ticks live on the skin of dogs.
4. Sea anemone is often found on the shell of hermit crab.

How can a woman, incapable of producing an ovum can become a mother?

A low level of expression of lac operon occurs at all the time. Can you explain the logic behind this phenomenon?

Name the negatively charged and positively charged components of a nucleosome.

OR

Name the positively charged protein around which the negatively charged DNA wrapped.

Define Ex-situ conservation.

Wheat is predator or grazing food chain? Give a suitable example.

Name the respective pattern of inheritance where F₁-phenotype

1. Does not resemble either of the two parents and is in between the two.
2. Resembles only one of the two parents.