Carrier proteins pick up specific molecules and take them through the cell membrane against the concentration gradient. Examples of active transport include: uptake of glucose by epithelial cells in the villi of the small intestine. uptake of ions from soil water by root hair cells in plants.
The last one, I believe.
This is a male, with three copies of chromosomes 21
Hope it helps :D
I think its if one parent has no alleles for the disease.
Answer:
A
Explanation:
natural selection depends on the variation in the traits of the organism. Those who are able to survive the catastrophic are able to pass their offspring to the next generation.
