The fossils that provide information on the formation of an oxygen-rich atmosphere are the stromatilites from the Precambrian era. These are layered and columnar fossils consisting mainly of cyanobacteria which were the original life form back then. These bacteria took in carbon dioxide and produced oxygen by photosynthesis as early as 2.5 billion years ago (the earth is about 4.5 billion yrs old).
<span>M (mitosis) phase is itself composed of two tightly coupled processes: mitosis, in which the cell's chromosomes are divided between the two daughter cells, and cytokinesis, in which the cell's cytoplasm divides in half forming distinct cells.</span>
Answer:
1. reducing soil erosion,
2.Controlling runoff water
Explanation:
Contour farming mitigates the impacts of floods, storms and landslides on the crops by reducing soil erosion up to 50 percent, controlling runoff water, increasing moisture infiltration and retention and thus enhancing soil quality and composition
Include low birth weight, maternal diabetes, older paternal age,
Answer:
Parental genotypes: RrBb, RRBB
Offspring phenotype: Running and black hair
Explanation:
Given, Running (R) is dominant over waltzing (r)
Black hair (B) is dominant over brown hair (b)
Parent 1: Heterozygous running, heterozygous black = RrBb
Parent 2: Homozygous running, homozygous black = RRBB
When they mate ( RrBb X RRBB ) :
Gametes produced by RrBb = RB, Rb, rB, rb
Gametes produced by RRBB = RB
Offspring:
RB Rb rB rb
RB RRBB RRBb RrBB RrBb
All offspring mice will be running mice and will have black hair because all the four types of genotype at least have one dominant allele for both the genes.
