A physical environment with different species that interact with one another and with non-living thing is called an ecosystem
Since you forgot to put capital letters i assume it's like this:
1)A <span>Cross between YyLl (heterozygous parent with dominant traits) and yyll (homozygous parent with recessive traits).
</span><span> 2)offspring YyLl: 400, Yyll: 100, yyLl: 100 and yyll: 400
</span>The recombinant offspring are allele combinations that are not directly inherited from the parents.
The parents combinations:<span>YyLl and yyll,
</span>The recombinant combinations: Yyll and yyLl
The other types are exacly like the parents so they are not recombinant.
answer: Yyll and yyLl
Explanation: because carry out all the functions in the human body necessary for living. Proteins make up hormones that are required for living. Insulin - responsible for stabilising blood sugar. Haemoglobin - responsible for carrying oxygen around the body. Melatonin - responsible for helping us get to sleep. Adrenalin - responsible for the flight-fight-freeze response. There are many more but here are just a few.
It's B
Explanation:
Because the fossil record shows how organisms have evoluate from relatively simple organisms to more complex organisms
B) One swims freely and the other often lives attached to a hard surface.