Visiting Mars is the next big chalenge in space (explore).

Future Mars exploration missions will present scientists and astronauts alike with a host of problem that will challenge human survival. Accessing water, dealing with a frigid planet that lacks oxygen and coping with dangerous levels of radiation are among the biggest hurdles to overcome.

Explanation:

Explanation:

What are some of the challenges in exploring Mars?

Every challenge astronauts will face on a flight to Mars

The flight trajectory for Mars and corrective maneuvers.

Spacecraft and fuel management.

Radiation, microgravity, and astronaut health.

Isolation and psychological issues.

Communications (in transit and on Mars)

The Mars approach and orbital insertion.

you didn't list the options but im guessing it's resolving contradictions

answer: b (host)

viruses use the cells of living organisms to reproduce. the cell which is used by virus is called as "host cell". it is a living cell in which virus multiplies, example bacteria, plant or an animal cell.

in this, the virus is a parasite, which uses host cell for its benefit (reproduction) by using the cell machinary of host cell.