Please help me ASAP TvT How does crossing-over result in genetic recombination?

- It permits the exchange of genetic material between homologous chromosomes.

- It reduces the original cell’s chromosome number by half.

- It mixes half the maternal chromosomes with half the paternal chromosomes.

- It randomly separates the maternal and paternal chromosomes.

Four types of motile cells in human body?

Tara sees a commercial for a brand of pills that promise to boost energy and people perform better in work and school. as people in the commercial talk about how much better they feel when taking the pill, tara notices a message on the bottom of the screen that reads, "this pill is not approved by doctors and has not been tested in controlled experiments." what is the best conclusion that tara should make about the commercial? it is making scientific claims based on subjective observations. it is making scientific claims based on opinions instead of pseudoscientific facts. it is making pseudoscientific claims based on objective observations. it is making pseudoscientific claims based on opinions instead of scientific facts.

When is your respiration rate likely to change? a. when your intestines are digesting b. when your cells have too much glucose c. when your cells need more oxygen d. when your liver is working after a meal