True
Because one of the environmental catastrophes is dust bowl
The option which is not a characteristic of chordates is chloroplasts in their cells.
Chordates do have a dorsal supporting rod (vertebrates are types of chordates - they have a spine), a dorsal hollow nerve cord (within the spine), and pharyngeal pouches. However, they do not have chloroplasts, because that is a characteristic of photoautothropic eukaryotes, which chordates certainly are not.
Answer:
of the low pH of the vagina.
Explanation:
The pH of the vagina is maintained at highly acidic levels to prevent the germ buildup. The range of vaginal pH is around 3.8 to 4.5. The very low pH of the vagina creates a hostile environment for sperms and most of the sperms are killed as they enter the vagina due to the acidic pH.
Apart from supplementing the sperms with energy, cervical mucus serves to protect the sperms from the hostile conditions of the vagina. The cervical mucus has an alkaline pH at or near the ovulation to protect sperms from acidic pH of the vagina and to facilitate fertilization.
Well I won't go to tooooooo much of that detail but the thing is FACT BY ME that everything around u is science and when u learn about ur surroundings it is science...!!!!
Natural selection and speciation: 'Ecological speciation'. ... Natural selection is generally recognized as a central mechanism of evolutionary change within species. Thus, natural selection plays a major role in generating the array of phenotypic and genetic diversity observed in nature.
