Answer:
b. completely by mitosis
Explanation:
Mitosis is a process of cell duplication in which one cell gives rise to two genetically identical daughter cells. Strictly applied, the term mitosis is used to describe the duplication and distribution of chromosomes, the structures that carry the genetic information. In the context of the cell cycle, mitosis is the part of the division process in which the DNA of the cell's nucleus is split into two equal sets of chromosomes.
Answer:
- Crystallization (cooling or solidification)
- Erosion and sedimentation (lithification, burial and deposition)
- Metamorphism (Melting due to heat and pressure)
Explanation:
In rock cycle, there are three important processes that changes one type of rocks into another type. Those processes are:
- <u>Crystallization:</u> It is a process that takes place under the earth surface where magma cools down and is hardened to form igneous rocks. This process is also called freezing of rocks.
- <u>Erosion and sedimentation:</u> The rocks on the surface of earth are broken into smaller fragments called sediments that are formed by weathering of rocks. These sediments are then carried either by wind or water to different places and settles at some place to form another type of rock named sedimentary rocks.
- <u>Metamorphism:</u> Metamorphism takes place under the earth surface where extreme heat changes the mineral texture of the rock but does not melt it. such rocks are named as metamorphic rocks.
Answer:
Gametogenesis is the formation of gametes, in males it is referred as spermatogenesis and in females it is called oogenesis.
Explanation:
Differences between spermatogenesis and oogenesis:
1. Spermatogenesis is formation of sperms from spermatogonia and oogenesis is formation of ova from oogonium.
2. Location: Production of sperms occur in testis and production of ova occurs in ovaries.
3. In males, spermatogenesis begins at puberty and its a continuous process till death whereas in females, oogenesis begins at fetal stages, it halts and rest of the process occurs after puberty till menopause.
4. Primary spermatocyte undergoes meiosis-I to form two secondary spermatocytes, whereas primary oocyte undergoes to M-I to form a single secondary oocyte with a polar body.
5. Meiosis-II results in the formation of 4 spermatids or spermatozoa, in females however M-II results in only one ovum and second polar body formation.
6. Overall we can say that single spermatogonium forms 4 spermatids whereas single oogonium forms only 1 ovum.
7. Sperms are motile where as ovum in non-motile.