Which of the following statements correctly the full value of a keystone species on its ecological community

Football players often sustain lateral blows to the extended knee. which of the ligaments is (are) damaged as a result? a. suprapatellar b. oblique popliteal and extracapsular ligament c. medial collateral, medial meniscus, and anterior cruciate d. arcuate popliteal and the posterior cruciate

Fan egg cell containing the (n+1) number of chromosomes combines with a sperm cell containing the (n) number of chromosomes, what is the result of this union? a) all future somatic cells of the organism will contain the (2n + 1) number of chromosomes. b) all future somatic cells of the organism will contain the (2n - 1) number of chromosomes. c) only certain somatic cells of the organism will contain the (2n + 1) number of chromosomes. d) all future somatic cells of the organism will contain the normal diploid number of chromosomes.

Some birds look for food near cattle and other livestock. the movement of the cattle churns up the ground, making insects available to the birds. the cattle appear to be unaffected by the presence of the birds. what kind of relationship exists between the birds and the cattle? o a. parasitism o b. commensalism o c. predation o d. mutualism