Tag: biology

Erich Tschermak was an Austrian agronomist who developed several new disease-resistant crops, including wheat-rye and oat hybrids. He independently rediscovered Gregor Mendel's work on genetics. He was a plant breeder, and his hybridization experiments were done with the idea of improving crops using the laws of heredity.

So, the correct option is ‘Austria’.

Hugo de Vries, Holland botanist and geneticist, is the author of the mutation theory of evolution. His work led to the rediscovery and establishment of Mendel's laws. He made his first notable contributions to science in the 1880s in the field of plant physiology.

So, the correct option is ‘Holland’.

Carl Erich Correns was a German botanist and geneticist, who is notable primarily for his independent discovery of the principles of heredity, and for his rediscovery of Gregor Mendel's earlier paper on that subject, which he achieved simultaneously but independently of the botanists Erich Tschermak von Seysenegg and Hugo de Vries, and the agronomist William Jasper Spillman.

So, the correct option is ‘German’.

Mendel’s laws of inheritance was rediscovered by Hugo de Vries, Carl Correns, and T.Schemark independently.

So, the correct option is ‘Von Tschemark’.

Hormones are the chemical substance, released from endocrine glands. They are directly released into the blood and affect the targeted organ. They may be the peptide such as insulin or steroid such as cortisol. Thus, the correct answer is option B.

A pheromone is a chemical released by one animal to affect the behaviour of another animal and thus it is used to trap the beetle to reduce their population.

Hormonal actions are regulated by two mechanisms: feedback and antagonistic effects of two hormones. A feedback mechanism can work as a negative or positive mechanism. The negative feedback mechanism is activated by surplus and proceeds to correct the process that caused the surplus. Therefore, increased the blood level of a certain hormone or its effect on target organ act to prevent its further release. For example, increased blood glucose level stimulates insulin secretion. The positive feedback mechanism of hormone regulation includes stimulation of release of the same hormone caused by its increased blood level. For example, the release of oxytocin is stimulated by uterine contraction during labor pain. 

Gonadotropin is a hormone which stimulates production of sex hormones and development of secondary sexual characters.
Females : Ovaries : Oestrogen and Progesterone
Males : Testes (testicle) : Testosterone.

When the secretion of hormone is controlled by the factors or other hormones it is called feedback control. For example, homeostasis means keeping the internal environment of the body constant. Hormones help in maintaining internal environment of the body. Thus, the correct answer is option B.

An increased amount of thyroxine in the blood exerts an inhibitory effect on the hypothalamus. in such a way that less of thyroid releasing hormone (TRH) and thyroid stimulating hormone (TSH) is produced respectively. This eventually results in a decrease in thyroxine. This is called negative feedback control.