Tag: biology

Questions Related to biology

Hormone which is not produced in women only during pregnancy is 

biology chemical coordination and integration hormones of placenta coordination in human beings- chemical control endocrine system in humans

  1. hCG

  2. hPL

  3. hCS

  4. Estrogen

Show answer
Correct Option: D
Explanation:

hCG (Human Chorionic Gonadotrophins), hPL (Human Placental Lactogen), hCS (human Chorionic somatomammotropin) are the hormones secreted by placenta so they are released during pregnancy only as the placenta is formed in pregnancy only. Placenta release other hormones as Estrogen and progesterone but these hormones are released by ovaries even in non-pregnant females. Therefore, hCG, hPL, and hCS are exclusively released in pregnancy from placenta.

So, the correct answer is 'Estrogen'.

Several hormones like hCG, hPL, Oestrogen, Progesterone are produced by

biology chemical coordination and integration hormones of placenta coordination in human beings- chemical control endocrine system in humans

  1. Ovary

  2. Placenta

  3. Fallopian tube

  4. Pituitary

Show answer
Correct Option: B
Explanation:
Hormones secreted by the placenta are  Estrogen, Progesterone, hCS, hPL & hCG. The placenta is an endocrine gland that is only present during pregnancy. hCG or the human chorionic gonadotrophin is secreted in excess amount in early pregnancy. IT's presence in urine is used for the pregnancy test. hCS or human placental somato mammotropin is also called placental lactogen. It acts a mild growth hormone. 
So the correct option is 'placenta'.

Choose the correct answers from the alternatives given.
The main role of placenta in embryonic development is to

biology chemical coordination and integration hormones of placenta coordination in human beings- chemical control endocrine system in humans

  1. act as storage organ

  2. convey nerve impulses

  3. provide essential requirements for growth of embryo

  4. protect embryo from shocks

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Correct Option: C
Explanation:

The placenta facilitates the supply of oxygen and nutrients to the embryo and also the removal of carbon dioxide and excretory/waste materials produced by the embryo.

So the correct option is 'provide essential requirements for growth of embryo'.

Fetal ejection reflex in human female is induced by

biology chemical coordination and integration hormones of placenta coordination in human beings- chemical control endocrine system in humans

  1. Pressure exerted by amniotic fluid

  2. Release of oxytocin from pituitary

  3. Fully developed foetus and placenta

  4. Differentiation of mammary glands

Show answer
Correct Option: C
Explanation:

The signals for parturition originates from the fully developed foetus and placenta, which induce mild uterine contractions called as foetal ejection reflex. This triggers the release of oxytocin, which is birth hormone from the maternal pituitary gland. This oxytocin starts a series of powerful contractions in the uterus to help expel the baby and limits bleeding of the placenta near the entry of the vaginal canal.
Thus, the correct answer is option (C).

Consider the following statements and choose the correct options.
I. Ovule is attached to the placenta by means of a stalk called filaments.
II. Ovule fuses with the stalk in the region called hilum.
III. The two protective envelopes of the ovule are called integuments.
IV. The small opening in the tip of ovule is called germ pore.

biology chemical coordination and integration hormones of placenta coordination in human beings- chemical control endocrine system in humans

  1. I and IV

  2. I and III

  3. II and IV

  4. II and III

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Correct Option: A

The prickly pear cactus became unusually abundant after its introduction in Australia, because it _________________.

biology adaptation terrestrial adaptations in plants adaptation in terrestrial plants terrestrial adaptation desert ecosystem terrestrial adaptation in animals

  1. had no co evolved herbivores

  2. formed new mycorrhizall association

  3. lost its thorns

  4. all of these

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Correct Option: A
Explanation:

Co evolution is caused by the selection pressure that each of the two species exerts on the other since there has been no co-evolved herbivore with prickly cactus, it became abundant in Australia.

Stems are covered by waxy coating in order to prevent

biology adaptation terrestrial adaptations in plants adaptation in terrestrial plants terrestrial adaptation desert ecosystem terrestrial adaptation in animals

  1. Loss of water

  2. Photosynthesis

  3. Loss of carbon dioxide

  4. None of these

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Correct Option: A
Explanation:

Stems are covered by waxy coating in order to prevent the loss of water and helps in maintaining the water level in the plant under dry conditions.

The process of change by which an organism or species becomes better suited to its environment is known 

biology adaptation terrestrial adaptations in plants adaptation in terrestrial plants terrestrial adaptation desert ecosystem terrestrial adaptation in animals

  1. Adaptation

  2. Migration

  3. Digestion

  4. None of these

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Correct Option: A
Explanation:

The process of change by which an organism or species becomes better suited to its environment is known as adaptation.

The trees in mountain habitats usually have

biology adaptation terrestrial adaptations in plants adaptation in terrestrial plants terrestrial adaptation desert ecosystem terrestrial adaptation in animals

  1. Cone shape

  2. Rectangle shape

  3. Oval shape

  4. Square shape

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Correct Option: A
Explanation:

The trees in mountain habitats usually have cone shape having sloping branches. This shape makes the rainwater and snow to slide off easily.

Which feature would be most helpful to a plant in a desert?

biology adaptation terrestrial adaptations in plants adaptation in terrestrial plants terrestrial adaptation desert ecosystem terrestrial adaptation in animals

  1. Small leaves

  2. Large seeds

  3. Small roots

  4. Smelly flowers

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Correct Option: A
Explanation:
Option A is correct.
Small leaves will help as they can reduce water loss due to transpiration.