Sickle cell anaemia has not been eliminated from the African population because :
- it is controlled by recessive genes
- it is not a fatal disease
- it provides immunity against malaria
- it is controlled by dominant genes
The Correct Option is C
Solution and Explanation
Sickle cell anemia has not been eliminated from the African population because it provides immunity against malaria. Heterozygous carriers of the sickle cell gene have some resistance to malaria, which is common in certain regions of Africa where the disease is prevalent.
Therefore, the correct option is (C): it provides immunity against malaria
Top Questions on Principles of Inheritance and Variation
Assertion (A): In dihybrid crosses involving sex-linked genes in \(\textit{Drosophila}\), generation of non-parental gene combinations are observed
Reason (R): Two genes present on different chromosomes show linkage and recombination in \(\textit{Drosophila.}\)- CBSE CLASS XII - 2025
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Explain how the addition of lactose in the medium regulates the switching on of the \(\textit{lac}\) operon in bacteria.
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Assertion (A) : In dihybrid crosses involving sex-linked genes in \(\textit{Drosophila}\), \(F_2\) generation of non-parental gene combinations are observed.
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Questions Asked in NEET exam
- With the help of the given pedigree, find out the probability for the birth of a child having no disease and being a carrier (has the disease mutation in one allele of the gene) in the F3 generation.
- NEET (UG) - 2025
- Genetics
- The plates of a parallel plate capacitor are separated by d. Two slabs of different dielectric constant \(K_1\) and \(K_2\) with thickness \(d/2\) and \(d/2\) respectively are inserted in the capacitor. Due to this, the capacitance becomes two times larger than when there is nothing between the plates. If \(K_1 = 1.25 K_2\), the value of \(K_2\) is :
- NEET (UG) - 2025
- Capacitors and Capacitance
A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is :
- NEET (UG) - 2025
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- Two cities X and Y are connected by a regular bus service with a bus leaving in either direction every T min. A girl is driving scooty with a speed of 60 km/h in the direction X to Y. She notices that a bus goes past her every 30 minutes in the direction of her motion, and every 10 minutes in the opposite direction. Choose the correct option for the period T of the bus service and the speed (assumed constant) of the buses.
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- A microscope has an objective of focal length \(f_o = 2\) cm and an eyepiece of focal length \(f_e = 4\) cm. The tube length of the microscope is \(L = 40\) cm. If the distance of distinct vision of eye is \(D = 25\) cm, the magnification in the microscope is:
- NEET (UG) - 2025
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Concepts Used:
Human Endocrine System
The human endocrine system is a messenger system that balances or controls distant target organs through feedback loops of hormones released by the internal glands of an organism right into the circulatory system. The hypothalamus is the neural control node for all endocrine systems, in invertebrates.
Functions of the Human Endocrine System are:
The endocrine system controls a variety of body functions through hormone release. Hormones are built by the endocrine system's glands and pass throughout the bloodstream to various organs and tissues in the body. Hormones then command these organs and tissues about how to act.
The Endocrine System is in charge of the following bodily functions:
- Metabolic rate
- Development and growth of a human being
- Reproduction and sexual function
- Heart Rate
- Blood pressure
- The appetite is the need to eat
- Controls cycles of sleep and wakefulness
- Controls the temperature of the body