Answer:
Two and a half billion years ago, single-celled organisms called cyanobacteria harnessed sunlight to split water molecules, producing energy to power their cells and releasing oxygen into an atmosphere that had previously had none.
Explanation:
Adding nitrogen to it through their root nodules.
The smallest particle of any type of matter would be an Atom
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.
The answer is C. large changes in allele frequencies can occur in a short time.
Genetic drift is a change in the frequency of alleles in a population as a result of random sampling of organisms and it decreases genetic variation of the population. In specific circumstances, large and rapid changes in allele frequencies can occur in a short time. The smaller the population, the more susceptible it is to genetic drift.