Explain how the appearance of photosynthetic organisms (bacteria, algae, and plants) changed the earth's atmosphere.

Mention true or false : a) cholera is marked by acute diarrhea and no urination. b)mosquitoes are the source of dysentery germs.

If the frequency of the p allele is .63 in the population then what is the frequency of the q allele?

When does a spring tide occur? question 9 options: they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur twice a year in the spring and fall. they occur on the date of the vernal equinox each year, no matter what stage the moon is in. this is why they are called spring tides. they occur when the sun, moon, and earth are at 45-degree angles from each other. this happens once every spring. they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur all year long.