Â©2003 Why is there a decision to make about having mammograms to screen for breast cancer? A mammogram every two years to screen for breast cancer reduces the chance of dying from breast cancer among women aged 50 to 69 years. It is unclear if women aged 70 years and older get the same benefits. mammogram every two years to screen for breast cancer reduces the chance of dying from breast cancer among women aged 50 to 69 years. It is unclear if women aged 70 years and older get the same benefits.
Temperate grasslands are located north of the Tropic of Cancer (23.5 degrees North) and south of the Tropic of Capricorn (23.5 degrees South). The major temperate grasslands include the veldts of Africa, the pampas of South America, the steppes of Eurasia, and the plains of North America.
Temperate grassland. Temperate grasslands are characterized as having grasses as the dominant vegetation. Trees and large shrubs are absent. Temperatures vary more from summer to winter, and the amount of rainfall is less in temperate grasslands than in savannas.rasslands are characterized as lands dominated by grasses rather than large shrubs or trees. In the Miocene and Pliocene Epochs, which spanned a period of about 25 million years, mountains rose in western North America and created a continental climate favorable to grasslands.