I want an answer i am really struggling solving this

here

Explanation:

a) Meiosis is required to provide genetic variation and to make sure that the number of chromosomes remain 46 in the zygote by producing haploid gametes.

b) Sperm cell's head contains the acrosome which has hydrolytic enzymes capable of dispersing the corona radiata (cell remnants from the follicle after ovulation) surrounding the ovum and penetrating the zona pellucida (glycoprotein coat surrounding the ovum's cell membrane).

The sperm's membrane then fuses with that of the ovum's, releasing its haploid nucleus inside the ovum, while its head, neck and tail remain on the outside.

The sperm's condensed nucleus expands and the female haploid nucleus undergoes meiosis-II before the nuclei fuse together to form the diploid zygote. This is fertilisation.

It is important to note that after the first sperm's penetration, the zona pellucida will modify its sperm receptors so that no other sperms can enter the ovum. It becomes impermeable.

c)

i) 16 cells (4^2)- if you don't remember the formula, you can draw it and count.

ii) It doesnt increase in size because the zona pellucida remains intact for a few days (5 to be specific) after fertilization.

answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c