Given below are the names of certain stages/substances related to reproduction and found in human body. Answer the questions related to them,

(a) Foetus.

● Where is it contained?

● How does it differ from an embryo?

(b) Hyaluronidase.

● Is it an enzyme or simply a protein?

● What is its function?

(c) Morula.

● What is this stage?

● Name the stage which comes next to it?

(d) Amniotic fluid.

● Where is it found?

● What are its functions?

(e) Gestation.

● What is its meaning?

● How long does it normally last?

(f) placenta.

● What are the two sources that form placenta? Name any two main substances which pass from foetus to mother through the placenta.

● Name any two main substances which pass from fetus to mother through the placenta.

● Name any two hormones it produces.

(g) Implantation.

● The development stage that undergoes this process.

●The approximate time after fertilization, when it occurs.

(a) 1. It is contained in the uterus.

2. In the foetus, limbs have appeared and resembles the humans, unlike the embryo which is a growing or dividing zygote.

(b) 1. Enzyme

2. It is an enzyme secreted by the sperm that allows the sperm to penetrate the egg.

(c) 1. It is the stage in the development of human embryo which consists of a spherical mass of cells.

2. Blastocyst.

(d) 1. Between amnion and embryo

2. It protects the embryo from physical damage, keeps the pressure all around embryo and prevents sticking of the foetus to amnion.

(e) 1. Gestation is the full term of the development of an embryo in the uterus.

2. 280 days in humans.

(f) 1. Placenta is formed by two sets of minute finger-like processes called the villi. One set of villi is from the uterine wall and the other set is from the allantois.

2. Oxygen and amino acids.

3. Progesterone and oestrogen.

(g) 1. Blastocyst

2. It occurs in about 5-7 days after ovulation.