Explain how GM cotton crop is able to resist insect attacks.
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Solution and Explanation
GM cotton expresses a gene from Bacillus thuringiensis that produces a toxic protein: The Bt toxin is ingested by bollworms. The toxin binds to receptors in the insect gut, causing cell lysis and death.
Top Questions on Ecology
Two important characteristics for estimating any population of animals and plants are \(\underline{\hspace{2cm}}\) and \(\underline{\hspace{2cm}}\) of individuals.
- Match List-I with List-II
\[\begin{array}{|l|l|} \hline \textbf{List-I} & \textbf{List-II} \\ \hline \text{(A). Population size} & \text{(I). It refers to how many individuals reside in a particular area} \\ \hline \text{(B). Population density} & \text{(II). It yields helpful information about how species interact with each other} \\ \hline \text{(C). Population distribution} & \text{(III). It represents the total number of individuals in a habitat} \\ \hline \text{(D). Population dispersion} & \text{(IV). It describes how individuals of a species are spread out, whether they live in close proximity} \\ \hline \text{to each other or far apart, or clustered into groups} \\ \hline \end{array}\]
Choose the correct answer from the options given below: Demography is the study of factors that affect \(\underline{\hspace{2cm}}\) and \(\underline{\hspace{2cm}}\) patterns.
- Arrange the following stages of ecological succession in the correct sequence
A. Ecesis
B. Nudation
C. Aggregation
D. Reaction
Choose the most appropriate answer from the options given below: - Match LIST-I with LIST-II
\begin{tabularx}{0.9\textwidth}{|l|X|l|X|} \hline \multicolumn{2}{|c|}{LIST-I} & \multicolumn{2}{c|}{LIST-II}
\multicolumn{2}{|c|}{Interaction Type} & \multicolumn{2}{c|}{Example}
\hline A. & Mutualism & I. & Chlorella vulgaris and Diatoms
B. & Commensalism & II. & Termites and Trichonympha
C. & Proto-cooperation & III. & Intestine of Man and Entamoeba coli
D. & Antibiosis & IV. & Adamsia pallia and hermit crab
\hline \end{tabularx}
Choose the most appropriate answer from the options given below:
Questions Asked in CBSE CLASS XII exam
A ladder of fixed length \( h \) is to be placed along the wall such that it is free to move along the height of the wall.
Based upon the above information, answer the following questions:(iii) (b) If the foot of the ladder, whose length is 5 m, is being pulled towards the wall such that the rate of decrease of distance \( y \) is \( 2 \, \text{m/s} \), then at what rate is the height on the wall \( x \) increasing when the foot of the ladder is 3 m away from the wall?
- CBSE CLASS XII - 2025
- Application of derivatives
- A meeting will be held only if all three members A, B and C are present. The probability that member A does not turn up is 0.10, member B does not turn up is 0.20 and member C does not turn up is 0.05. The probability of the meeting being cancelled is:
- CBSE CLASS XII - 2025
- Probability
- Vishesh, Manik and Amit were partners in the ratio 5 : 4 : 1. Amit retired on 31st March, 2024. Vishesh and Manik decided to share Amit’s share in the ratio 2 : 3. What will be the new profit sharing ratio between Vishesh and Manik?
- CBSE CLASS XII - 2025
- Retirement and Death of a Partner
- The electric field in a region is given by \( \vec{E} = 40x \hat{i} \, \text{N/C}. \) Find the amount of work done in taking a unit positive charge from a point (0, 3m) to the point (5m, 0).
- CBSE CLASS XII - 2025
- Electrostatics
- Consider the Linear Programming Problem, where the objective function \[ Z = x + 4y \] needs to be minimized subject to the following constraints: \[ 2x + y \geq 1000, \] \[ x + 2y \geq 800, \] \[ x \geq 0, \quad y \geq 0. \] Draw a neat graph of the feasible region and find the minimum value of $Z$.
- CBSE CLASS XII - 2025
- Linear Programming Problem