Answer:
An asteroid impact.
Explanation:
An asteroid impact is considered to have tossed rubble across the earth, killing off many species of plants and animals, 65 million years ago. Volcanic activity is involved in at least four mass extinctions, whereas an asteroid in just one.
Answer:
B
Explanation:
Warm because land gains heat faster than water when heated by the sun. The heated land then transfers the heat to the atmosphere. The air mass is dry becasue a continent is mainly land and very little water (unlike oceans). There is, therefore, very little moisture in the continental tropical air mass.
Answer:
allele - different forms or versions of genes
chromosomes - structures that carry genetic information (passed from biological parents to offspring)
homologous - similar in structure
locus - a particular site or location
Explanation:
D it allows all substances to enter & exit the cell.