Whenever more than one individual or population in an ecosystem tries to make use of the same 'limited" recource this is referred as?

In natural selection, what is actually “selected? ” a) alleles are directly selected b) genotypes are directly selected c) phenotypes are directly selected d) entire populations are directly selected

What molecules does hemoglobin decay into over time

What are antigens and antibodies? how are they involved in the body’s response to incompatible blood?