$CATEGORY: Science - Khan Academy/8.How do Organisms Reproduce?/8.How do Organisms Reproduce?--Sexual Reproduction

//Multiple Choice

What is the main role of the placenta in mammals? {
    ~To protect the embryo from external injuries
    =To exchange nutrients, gases, and waste between the mother and fetus
    ~To produce gametes for reproduction
    ~To assist in the process of fertilization
}

In humans, the placenta is formed by the interaction between\: {
    ~Ovary and uterus
    ~Uterus and sperm
    =Uterus and embryonic tissues
    ~Ovum and uterus
}

Which hormone is secreted by the placenta during pregnancy? {
    ~Oxytocin
    =Progesterone
    ~Insulin
    ~Testosterone
}

The umbilical cord connects the fetus to the\: {
    ~Uterus
    =Placenta
    ~Amniotic sac
    ~Ovary
}

The placenta facilitates the transfer of oxygen and nutrients from\: {
    ~Fetus to mother
    =Mother to fetus
    ~Amniotic fluid to fetus
    ~Uterus to ovary
}

What type of blood vessel carries oxygenated blood from the placenta to the fetus? {
    =Umbilical vein
    ~Umbilical artery
    ~Pulmonary artery
    ~Aorta
}

Which of the following is NOT a function of the placenta? {
    ~Hormone production
    ~Nutrient exchange
    ~Excretion of fetal waste
    =Production of gametes
}

The placenta allows the diffusion of which substances from the mother to the fetus? {
    ~Oxygen and nutrients
    ~Carbon dioxide and waste
    ~Hormones and antibodies
    =All of the above
}

The process of implantation in humans occurs in the\: {
    ~Ovary
    ~Fallopian tube
    =Uterus
    ~Placenta
}

The structure that prevents the mixing of maternal and fetal blood in the placenta is the\: {
    =Placental barrier
    ~Umbilical cord
    ~Amniotic sac
    ~Endometrium
}

//True or False

Fertilization in humans occurs in the uterus. {F}

The placenta facilitates the exchange of nutrients, gases, and waste between the mother and the fetus. {T}

The umbilical cord contains two veins and one artery. {F}

Progesterone is a hormone secreted by the placenta during pregnancy. {T}

The zygote formed after fertilization is haploid. {F}

The placental barrier prevents the mixing of maternal and fetal blood. {T}

The umbilical vein carries oxygenated blood from the placenta to the fetus. {T}

Implantation of the embryo occurs in the ovary. {F}

The placenta also produces hormones to support pregnancy. {T}

In humans, the placenta is fully functional by the 12th week of pregnancy. {T}

//Fill in the blanks

The process of fusion of male and female gametes is called ________. {
    ~Pollination
    =Fertilization
    ~Germination
    ~Budding
}

The structure that connects the fetus to the placenta is called the ________. {
    ~Amniotic sac
    =Umbilical cord
    ~Fallopian tube
    ~Endometrium
}

The placenta allows the exchange of ________ between the mother and the fetus. {
    =Nutrients and gases
    ~Blood
    ~Hormones only
    ~Gametes
}

In humans, the placenta is fully developed by the ________ week of pregnancy. {
    ~4th
    =12th
    ~20th
    ~30th
}

The blood vessel that carries oxygenated blood from the placenta to the fetus is the ________. {
    ~Umbilical artery
    =Umbilical vein
    ~Pulmonary vein
    ~Aorta
}

The hormone produced by the placenta to maintain pregnancy is ________. {
    ~Estrogen
    =Progesterone
    ~Insulin
    ~Testosterone
}

The placenta is formed by the tissues of the uterus and the ________. {
    ~Ovary
    ~Zygote
    =Embryo
    ~Amniotic sac
}

The organ where fertilization occurs in humans is the ________. {
    ~Uterus
    ~Ovary
    =Fallopian tube
    ~Placenta
}

The structure that prevents the mixing of maternal and fetal blood is called the ________. {
    =Placental barrier
    ~Umbilical cord
    ~Endometrium
    ~Amniotic sac
}

The process of attachment of the embryo to the uterine wall is called ________. {
    ~Fertilization
    =Implantation
    ~Ovulation
    ~Menstruation
}

//Numericals

How many chromosomes are present in a human zygote? {
    ~23
    =46
    ~92
    ~21
}

How many umbilical arteries are present in the umbilical cord? {
    ~1
    =2
    ~3
    ~4
}

How many days after fertilization does implantation typically occur in humans? {
    ~2-3 days
    =5-6 days
    ~10-12 days
    ~15-20 days
}

How many chromosomes are present in a human gamete? {
    =23
    ~46
    ~92
    ~21
}

How many weeks does it take for the placenta to be fully functional in humans? {
    ~4 weeks
    ~8 weeks
    =12 weeks
    ~20 weeks
}

If the diploid chromosome number of an organism is 40, how many chromosomes are present in its gametes? {
    ~10
    =20
    ~40
    ~80
}

How many veins are present in the umbilical cord? {
    =1
    ~2
    ~3
    ~4
}

How many sperm cells are produced from 10 primary spermatocytes during meiosis? {
    ~20
    ~30
    =40
    ~50
}

How many chromosomes are present in the nucleus of a placental cell in humans? {
    ~23
    =46
    ~92
    ~21
}

How many ovules are needed to produce 15 seeds in a plant? {
    ~5
    ~10
    =15
    ~20
}

//Match the following

Match the following items from Column A with their correct corresponding options from Column B\:
{
=Fertilization -> Fallopian tube
=Implantation -> Uterus
=Placenta -> Nutrient exchange
=Umbilical cord -> Connects foetus to placenta
}


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